Antidepressant Exposure and DNA Methylation: Insights from a Methylome-Wide Association Study

Importance

Understanding antidepressant mechanisms could help design more effective and tolerated treatments.

Objective

Identify DNA methylation (DNAm) changes associated with antidepressant exposure.

Design

Case-control methylome-wide association studies (MWAS) of antidepressant exposure were performed from blood samples collected between 2006-2011 in Generation Scotland (GS). The summary statistics were tested for enrichment in specific tissues, gene ontologies and an independent MWAS in the Netherlands Study of Depression and Anxiety (NESDA). A methylation profile score (MPS) was derived and tested for its association with antidepressant exposure in eight independent cohorts, alongside prospective data from GS.

Setting

Cohorts; GS, NESDA, FTC, SHIP-Trend, FOR2107, LBC1936, MARS-UniDep, ALSPAC, E-Risk, and NTR.

Participants

Participants with DNAm data and self-report/prescription derived antidepressant exposure.

Main Outcomes and Measures

Whole-blood DNAm levels were assayed by the EPIC/450K Illumina array (9 studies, N exposed = 661, N unexposed = 9,575) alongside MBD-Seq in NESDA (N exposed = 398, N unexposed = 414). Antidepressant exposure was measured by self- report and/or antidepressant prescriptions.

Results

The self-report MWAS (N = 16,536, N exposed = 1,508, mean age = 48, 59% female) and the prescription-derived MWAS (N = 7,951, N exposed = 861, mean age = 47, 59% female), found hypermethylation at seven and four DNAm sites (p < 9.42x10 -8 ), respectively. The top locus was cg26277237 ( KANK1, p self-report = 9.3x10 -13 , p prescription = 6.1x10 -3 ). The self-report MWAS found a differentially methylated region, mapping to DGUOK-AS1 ( p adj = 5.0x10 -3 ) alongside significant enrichment for genes expressed in the amygdala, the "synaptic vesicle membrane" gene ontology and the top 1% of CpGs from the NESDA MWAS (OR = 1.39, p < 0.042). The MPS was associated with antidepressant exposure in meta-analysed data from external cohorts (N studies = 9, N = 10,236, N exposed = 661, f3 = 0.196, p < 1x10 -4 ).

Conclusions and Relevance

Antidepressant exposure is associated with changes in DNAm across different cohorts. Further investigation into these changes could inform on new targets for antidepressant treatments.

3 Key Points

Question: Is antidepressant exposure associated with differential whole blood DNA methylation?Findings: In this methylome-wide association study of 16,536 adults across Scotland, antidepressant exposure was significantly associated with hypermethylation at CpGs mapping to KANK1 and DGUOK-AS1. A methylation profile score trained on this sample was significantly associated with antidepressant exposure (pooled f3 [95%CI]=0.196 [0.105, 0.288], p < 1x10 -4 ) in a meta-analysis of external datasets. Meaning: Antidepressant exposure is associated with hypermethylation at KANK1 and DGUOK-AS1 , which have roles in mitochondrial metabolism and neurite outgrowth. If replicated in future studies, targeting these genes could inform the design of more effective and better tolerated treatments for depression.

Drug use among men who have sex with men in Ireland: Prevalence and associated factors from a national online survey

BACKGROUND

Little is known about the prevalence and determinants of drug use among men who have sex with men (MSM) in Ireland. The aims of this study were to measure the prevalence of recreational drug use among MSM in a national sample, and to identify sub-groups of MSM who may benefit from targeted preventive interventions.

METHODS

The MSM Internet Survey Ireland (MISI) 2015 was a community-recruited, nationally-promoted, self-completed online survey for MSM. MISI 2015 included standardised questions on recreational drugs, poppers, and drugs associated with chemsex (i.e. crystal methamphetamine, GBL/GHB, mephedrone, ketamine). Multivariable-adjusted logistic regression was used to identify factors associated with use of these substances.

RESULTS

In the previous year, 36% of MSM used recreational drugs, 33% used poppers, and 7% used drugs associated with chemsex. Five percent were diagnosed HIV-positive. Recreational drug users were significantly younger than non-users (median = 27 vs. 32 years; p < 0.001); popper users were significantly older than non-users (median = 34 vs. 28 years; p < 0.001). The odds of recreational drug use were higher among MSM diagnosed HIV-positive (vs. never tested; AOR 2.27, 95%CI 1.39-3.70). Use of poppers, and use of drugs associated with chemsex, were also higher among MSM diagnosed HIV-positive (vs. never tested; AOR 3.77, 95%CI 2.41-5.90, and AOR 5.87, 95%CI 3.08-11.18 respectively).

CONCLUSIONS

The prevalence of recreational drug use is higher among MSM than in the general population in Ireland, and it is particularly high among MSM diagnosed HIV-positive. Targeted harm reduction messages and preventive interventions are warranted to complement population-based approaches to reducing drug use in this population.

Inequalities in HIV testing uptake and needs among men who have sex with men living in Ireland: findings from an internet survey

OBJECTIVES

HIV disproportionately affects men who have sex with men (MSM) in Ireland. The aim of this study was to improve understanding of HIV testing among MSM living in Ireland to inform prevention and testing initiatives.

METHODS

We used data from the MSM Internet Survey Ireland 2015 (MISI 2015), a cross-sectional survey of MSM living in Ireland. We identified factors associated with never having tested for HIV using univariable and multivariable logistic regression. We identified preferred sites for future tests and examined the relationships between unmet HIV testing needs and socio-demographic groups.

RESULTS

More than one-third (n = 1006; 36%) of MSM had never tested for HIV. Multivariable logistic regression showed that untested men were more likely to be aged 18-24 years, live outside Dublin, have a lower level of education, be born in Ireland, identify as bisexual, be out to fewer people, and not have had sex with a man in the previous 12 months. The same groups of men also had the least knowledge about HIV and were least confident in accessing an HIV test. Men who had never tested for HIV were more likely to prefer testing by their general practitioner (GP) or using home sampling HIV kits and less likely to prefer testing in a sexual health clinic.

CONCLUSIONS

HIV prevention and testing programmes for MSM should be targeted towards younger men, those living outside Dublin and those with lower levels of education. We recommend increased promotion and availability of free HIV testing services in a range of clinical and nonclinical settings (including self-sampling and home testing).

Pilot evaluation of an online weight management programme

This intervention examined the efficacy of a six-week online weight loss programme. Students and staff of a third level institution (n=183) were recruited to the programme which provided individualised dietary advice for weight loss. Eighty-five participants (mean age 29.7 years, mean BMI 28.9kg/m2, 33% male) met the minimum inclusion criterion of logging on to the study website at least twice. All participants who completed the full six-week programme lost weight (n=31), with significant reductions in mean weight (2.8kg), BMI (0.9kg/m2) and waist circumference (4.1cm) observed between the start and end of the programme (all P<0.001). Among "completers", males lost more weight than females (4.2kg vs. 1.9kg, P=0.004). One in four completers lost >5% of their bodyweight, with reductions in biscuit and alcohol consumption being most predictive of weight loss. These findings suggest that individualised online dietary advice is effective in achieving short-term weight loss, especially in males.

Residual feed intake adjusted for backfat thickness and feeding frequency is independent of fertility in beef heifers

Basarab, J. A., Colazo, M. G., Ambrose, D. J., Novak, S., McCartney, D. and Baron, V. S. 2011. Residual feed intake adjusted for backfat thickness and feeding frequency is independent of fertility in beef heifers. Can. J. Anim. Sci. 91: 573–584. This study examined the effects of residual feed intake (RFI), RFI adjusted for off-test backfat thickness (RFIfat) and RFI adjusted for off-test backfat thickness and feeding event frequency (RFIfat & activity) on heifer fertility and productivity. Beef heifers (n=190) were monitored for individual daily feed intake and feeding event activity over 108–112 d using the GrowSafe System® and assessed for age at puberty based on plasma progesterone concentration. Individual animal daily feed intake, feeding event activity and off-test backfat thickness were then used to calculate RFI, RFIfat and RFIfat & activity and group heifers as either negative ([−], RFI<0.0) or positive ([+], RFI≥0.0) for RFI. Heifers averaged 298 kg (SD=34) in body weight, were 276 days of age (SD=19) at the start of test, grew at 0.90 kg d−1 (SD=0.21), consumed 7.62 kg DM head−1 d−1 (SD=0.84) and had a feed conversion ratio of 8.93 (SD=2.43). Age (351 d, SD=43) and weight (367.3 kg, SD=45.0) at puberty were similar between [−] and [+] RFI heifers, but age at puberty was delayed in [−] RFIfat (P=0.04) and RFIfat & activity (P=0.08) heifers compared with [+] RFIfat and RFIfat & activity heifers. Efficient or [−] RFI heifer exhibited a lower pregnancy (76.84 vs. 86.32%, P=0.09) and calving rate (72.63 vs. 84.21%, P=0.05) compared with [+] RFI heifers. These differences were partially removed in [−] RFIfat and completely removed in [−] RFIfat & activity compared with their [+] RFI counterparts (pregnancy rate, 80.85 vs. 82.29%, P=0.80; calving rate, 75.53 vs. 81.25%, P=0.34). No differences were observed between efficient and inefficient heifers in calving difficulty, average calving date, age at first calving, calf birth weight, calf pre-weaning ADG, calf weaning weight and heifer productivity. However, [+] RFI heifers exhibited a 1.9-fold higher calf death loss compared with [−] RFI heifers (11.11% vs. 5.71%, P=0.24). This difference was more pronounced in [+] RFIfat and [+] RFIfat & activity heifers, which exhibited 2.2-fold (11.84% vs. 5.33%, P=0.15) and 3.0-fold (12.66% vs. 4.17%, P=0.06) higher calf death loss compared with [−] RFI heifers. There was no relationship of RFI adjusted for backfat thickness and feeding activity on fertility traits indicating that backfat thickness and feeding activity may be associated with feed intake and should be considered when selecting heifers for improved feed efficiency.

Evidence of residual feed intake reranking in crossbred replacement heifers

The objective of the study was to examine whether residual feed intake (RFI) reranking exists between 2 consecutive periods in replacement heifers fed the same diet. The study collected feed intake and BW data from 190 crossbred heifers over a 3-yr period (61 in 2007, 68 in 2008, and 61 in 2009) during the winter-spring season. The heifers were fed a roughage-based diet (90% barley silage and 10% rolled barley grain) throughout the feeding trial, which was broken down into 2 feeding periods with ADG of 0.94 and 0.90 kg•d(-1) in the first and second periods, respectively. The RFI was calculated for the entire period using different models, which included ADG, mid-metabolic BW, body composition, and feeding activity. Gain:feed ratio and Kleiber ratio were also calculated. Rank correlations among the RFI calculated from different models were obtained, as well as rank correlations between the 2 feeding periods for the feed efficiency measures. Including body composition and feeding activity only improved the R(2) by 1 to 5%. The rank correlations among the different models were high (90 to 95%) for RFI calculated for the entire feeding period. However, the RFI calculated within the second feeding period had greater rank correlation than the RFI calculated from the entire feeding period. Compared with G:F and Kleiber ratio, RFI gave lesser reranking between periods 1 and 2. About 49% of the heifers maintained their RFI class, whereas 51% of the heifers had a different RFI class in period 2. Furthermore, 41% of the heifers changed their RFI in period 2 by <0.5 SD, whereas the rest of the heifers changed by ≥0.5 SD. These results indicate that reranking exists in heifers despite receiving the same diet in the 2 feeding periods and that the reranking may be more serious in heifers (28%) with extreme RFI performances in each period.

Potential of warm-season annual forages and Brassica crops for grazing: A Canadian Review

Extension of the grazing season beyond the normal perennial grazing season has been identified as a potential mechanism to reduce the cost of production on Canadian cow-calf operations. This review will provide an overview of the potential use of warm-season and Brassica crops including corn (Zea mays), Golden German foxtail millet (Setaria italica L. Beauv.), kale (Brassica oleracea L.), forage rape (B. napus ssp. biennis L.) and turnip (B. rapa L.). These crops have a high yield potential, but the cost for grazing these crops has not been adequately compared with the cost of grazing oat (Avena sativa L.), barley (Hordeum vulgare L.), and fall rye (Secale cereale L.). There are very few actual animal grazing trials evaluating the economics of using these crops in grazing systems in Canada, and this requires further research.Key words: Corn, millet, sorgum, sudan grass, fodder crops, brassicas

Annual cool season crops for grazing by beef cattle. A Canadian Review

With the current high feed grain costs and other economic uncertainties in the Canadian beef cattle industry, producers are trying to lower their unit costs of production. Costs can be lowered through extension of the grazing season using perennial pastures and annual crops for grazing. Oat (Avena sativa L.) and fall rye (Secale cereale L.) have traditionally been used to a nominal extent for extending the grazing season. However, there is limited information including a small number of animal grazing trials on the use of other annual cereals and annual ryegrass (Lolium multiflorum Lam.) for low cost grazing systems relative to feeding traditional harvested and stored forages. This review discusses annual cool season crops that show promise for supplementary grazing systems. Systems such as swath grazing of a cereal crop, grazing the regrowth from silage mixtures of spring and winter cereals, or fall grazing annual Italian ryegrass can be used to extend the grazing season. Economic considerations will ultimately determine if there will be an increased role in the future for grazing annual crops on cropping land as a means of extending the grazing season to reduce year-round costs for the beef cow calf operator. Key words: Small grain cereals, annual ryegrass, extended grazing, forage quality

Relationships between progeny residual feed intake and dam productivity traits

Two hundred and twenty-two yearling calves and their dams were used to examine the phenotypic (rp) relationships between progeny residual feed intake (RFI) and maternal productivity across 10 production cycles. Progeny RFI ranged from -3.95 to +2.72 kg as fed d-1 (SD = 0.94), while RFI adjusted for off-test backfat thickness (RFIadj), ranged from -2.48 to +1.53 kg as fed d-1 (SD = 0.88). Progeny RFI and RFIadj were unrelated to on-test age, body weight, growth rate, and ultrasound longissimus thoracis area and positively related to feed intake (rp = 0.51 to 0.53; P < 0.001), feed to gain ratio (rp = 0.44 to 0.46; P < 0.001), feeding behaviour traits (rp = 0.29 to 0.36; P < 0.001) and cow RFI (rp = 0.30, P < 0.05). Progeny RFI was positively related to measures of body fat (rp = 0.21 to 0.27; P < 0.05), but these relationships disappeared when RFI was adjusted for off-test backfat thickness. Cows that had produced LOW (≤ 0.5 SD), MEDIUM (± 0.5 SD) or HIGH (≥ 0.5 SD) RFIadj progeny were similar in pregnancy (95.6 vs. 95.3 vs. 96.0%, P = 0.90), calving (84.9 vs. 83.4 vs. 86.3%, P = 0.62) and weaning (81.5 vs. 80.2 vs. 82.3%, P = 0.79) rates. However, cows that produced HIGH RFIadj progeny had a higher twinning rate (3.77 vs. 0.35 vs. 0.00%, P < 0.001) and an increased calf death loss (8.06 vs. 4.24 vs. 4.02%, P = 0.10) compared with cows that produced MEDIUM or LOW RFIadj progeny. Cow body weight over 10 production cycles was similar at weaning, pre-calving and pre-breeding for dams that had produced LOW, MEDIUM and HIGH RFIadj progeny, and dams that produced LOW RFIadj progeny consistently averaged 2–3 mm more back fat thickness than dams that produced HIGH RFIadj progeny. Calf birth weight, pre-weaning ADG and 200-d weight, and cow production efficiency and calving interval were similar among dams that produced LOW, MEDIUM and HIGH RFIadj progeny. In addition, dams that produced LOW RFIadj progeny consumed less feed during their second trimester of pregnancy (10.9 vs. 11.6 vs. 12.2 kg DM d-1, P < 0.05), had lower RFI values (-0.05 vs. 0.44 vs. 1.88 kg as fed d-1, P = 0.018) and calved later in the year (96 vs. 90 vs. 91 d Julian, P < 0.001) than dams that produced MEDIUM and HIGH RFIadj progeny. These results showed that efficient RFI progeny and dams consumed less feed, had improved feed to gain ratio and spent less time in feed activity than inefficient cows and calves. In addition, cows that produced efficient calves were fatter, had fewer twins, less calf death loss and produced the same weight of calf weaned per cow exposed to breeding compared with cows that produced inefficient progeny. However, cows that produced efficient or low RFI progeny calved 5–6 d later in the year than cows that produced inefficient or high RFI progeny, indicating a need to monitor reproductive fitness in low RFI replacement heifers and breeding bulls. Key words: Residual feed intake, cow reproduction, lifetime production efficiency

Alternative fall and winter feeding systems for spring calving beef cows

This study evaluated the effects of early (EW) and late (LW) weaning on calf post-weaning growth performance and carcass characteristics. It also quantified the effects of EW and LW in combination with three winter feeding strategies on cow growth, reproductive performance and cost of production. EW calves were weaned in late August, while LW calves were weaned 56 d later in late October. The three cow winter feeding strategies were: (1) traditional (TD), or straw fed ad libitum and barley (Hordeum vulgare L.) silage fed every day; (2) alternate day (AD), or straw fed ad libitum and equivalent amounts of barley silage fed every second day (AD); and (3) swath graze (SG), or swath grazing whole-plant barley, cut in the soft dough stage. The study was conducted over three production cycles (1997/1998, 1998/1999 and 1999/2000). EW calves weighing 213 kg and fed a backgrounding diet (82% barley silage: 18% concentrate) for 56 d, grew 0.36 kg d-1 (EW = 0.61 ± 0.02 kg d-1; LW = 0.97 ± 0.02 kg d-1; P < 0.001) slower from early to late weaning than LW calves (210 kg) on pasture nursing their mothers. Over the next 124–128 d, EW and LW calves fed the backgrounding diet grew similarly at 0.95 ± 0.01 and 0.93 ± 0.02 kg d-1, respectively. Both groups of calves also grew similarly during the finishing phase (EW = 1.56 ± 0.04 kg d-1; LW = 1.53 ± 0.05 kg d-1; P = 0.62), such that at slaughter, EW and LW calves were the same age (461 ± 4 vs. 455 ± 5 d, P = 0.326) and weight (522 ± 5 vs. 515 ± 6 kg, P = 0.390), with similar levels of carcass backfat, yield and quality grade. EW cows weighed 12 to 15 kg more (P < 0.01) in mid-November (first winter feeding), mid-February (pre-calving) and late-May (prebreeding) and tended to have a shorter calving span (49 vs. 62 d, P = 0.07) than the LW cows. Calving interval, calving pattern and cumulative open and cull rates, monitored over three consecutive production cycles, were similar for EW and LW cows. Differences (P < 0.05) in body weight were observed between winter feeding treatments. SG cows had the lowest weight (605 kg) and backfat thickness (4.5 mm) at pre-breeding; AD cows were intermediate (623 kg and 5.1 mm); and TD cows were heaviest (639 kg) with the most backfat (6.4 mm). Calving interval, length of the calving span, calving pattern and cumulative open and cull rates were similar among the winter feeding strategies for cows monitored over three production cycles. Swath grazing required 38.4% less labour than traditional feeding and 20.9% less labour than alternate day winter feeding. Total cash cost over the first 100 d of winter feeding for the SG winter feeding strategy was $70.00 cow-1 less than TD (45.5%) and $56.70 cow-1 less than AD (40.4%) winter feeding strategies. On average, 300 and 314 cow swath grazing d ha-1 were required to cover the cost of feed in the TD and AD winter feeding strategies, respectively. Key words: Beef cows, Western Canadian Parkland, swath grazing, alternate day, early and late weaning

Frequency of concentrate supplementation for cattle fed barley straw. 1. Effect on voluntary intake, ruminal straw disappearance, apparent digestibility and heat production

Five ruminally cannulated crossbred steers (474 ± 30 kg) were fed diets containing 70% barley straw and 30% concentrate in an unbalanced 5 × 5 Latin square design experiment to investigate the effects of frequency of feeding barley grain-based concentrates (daily, alternate days or every third day) with different dietary protein (7.9 and 11.5%) on voluntary intake of straw, ruminal disappearance of straw, apparent digestibility, and heat production. Neither frequency of feeding nor dietary protein concentration influenced voluntary intake of straw, nor did cattle eat differing amounts of straw on days when concentrate was fed in comparison with days when concentrate was not fed. Protein supplementation increased (P < 0.01) 24-h ruminal straw disappearance, but did not affect disappearances at other times. Concentrate feeding frequency had no influence on rate of ruminal disappearance of straw. Apparent digestibilities of dry matter, gross energy, acid detergent fibre (ADF) and crude protein were 5, 6, 8 and 33% higher (P < 0.05), respectively, in diets containing the high-protein concentrate, but were not affected by frequency of concentrate feeding. Heat production (kJ kg-0.75) tended to be reduced (P = 0.06) by 4% in steers fed concentrate on alternate days in comparison with steers fed concentrate daily. Dietary protein concentration had no influence on heat production even though digestible energy intake was 10% higher when the high protein concentrate diet was fed. It was concluded that concentrate can be fed every second day without any negative impact on intake and digestibility, with a possible benefit of a reduction in energy lost as heat. More research, however, is required to study the feasibility of feeding concentrate every third day. Key words: Cattle, straw, protein, feeding frequency, digestion, heat production

Frequency of concentrate supplementation for cattle fed barley straw. 2. Ruminal dilution rates, pH and metabolite concentrations

Five ruminally cannulated crossbred steers (474 ± 30 kg) were fed diets containing 70% barley straw and 30% concentrate in an unbalanced 5 × 5 Latin square design experiment to in vestigate the effects of frequency of feeding concentrate (daily, alternate days or every third day) with different dietary protein concentrations (7.9 and 11.5%) on ruminal liquid and particulate dilution rates, pH and metabolite concentrations. Dilution rates of cobalt-ethylene diamine tetraacetic acid (Co- EDTA) and chromium-mordanted fibre did not differ when low- and high-protein concentrates were fed. Supplemental protein increased (P < 0.05) mean ruminal ammonia concentrations (3.3 vs. 1.6 mM), but had no influence on ruminal concentrations of organic acids. Frequency of concentrate feeding had no influence on dilution rate of digesta markers, pH or on mean ruminal concentrations of ammonia, lactic acid, propionic acid, isobutyric acid, valeric acid and isovaleric acid. Mean concentrations of total volatile fatty acids, acetic acid and butyric acid were, however, reduced (P < 0.05) when steers were fed concentrates on alternate days. The reduced (P < 0.01) ruminal acetic:propionic acid ratios observed in steers fed concentrates on alternate days were consistent with reduced heat productions. Positive relationships (P < 0.05) were obtained between heat production of steers and ruminal concentrations of isobutyric and valeric acids. It was concluded that the low-protein diet did not provide sufficient protein to meet microbial requirements and that under controlled feeding conditions cattle can be fed concentrate on alternate days or every third day without the occurrence of lactic acidosis. Additional research is warranted to examine the relationships between reduced heat production of steers fed concentrates on alternate days and ruminal concentration and production of organic acids. Key words: Cattle, straw, protein, feeding frequency, rumen metabolites, lactic acid

Feeding value of wheat-based thin stillage: in vitro protein degradability and effects on ruminal fermentation

Two experiments were conducted to evaluate the nutritive value of wheat-based thin stillage as a fluid source for ruminants. In vitro CP degradability of thin stillage was estimated relative to canola meal and heated canola meal in a completely randomized design. Four ruminally cannulated steers were used in a double cross-over design to determine the effects of consuming thin stillage or water as drinking sources on ruminal fermentation traits. The in vitro CP degradability of thin stillage (55.4%) was lower (P<.05) than that of canola meal (59.4%) and higher than that of heated canola meal (31.6%). Ruminal pH for steers consuming thin stillage was higher (P<.05) at 1000 and 1100 and lower (P<.05) at 1900 and 2000 than that for steers consuming water. Total VFA followed a pattern that was the reverse of that reported for pH. Ruminal NH3 N levels were higher (P<.05) for steers fed thin stillage than for water-fed steers through most of the collection period. Ruminal fluid and particulate matter passage rates were not affected by treatment and averaged .165 and .06 /h, respectively. The amount of thin stillage and water that did not equilibrate with the ruminal fluid and, thus, was considered to bypass the rumen was estimated to be 51.9 and 59.2% of total fluid consumed, respectively. Feeding wheat-based thin stillage had no adverse effects on ruminal metabolism.

Evaluation of wheat-based thin stillage as a water source for growing and finishing beef cattle

Two trials were conducted to evaluate the nutritional value of wheat-based thin stillage as a water source for cattle. In Trial 1, 20 large-framed steers were fed a basal diet based primarily on barley grain and barley silage, with ad libitum access to water or thin stillage at one of three DM concentrations (2, 4, and 6.7%) in a completely randomized design. The trial consisted of a 70-d growing period and a finishing phase. In Trial 2, total-tract nutrient digestibility coefficients of the basal diet and water treatments fed in the growing period were determined in a randomized complete block design using 12 medium-framed steers. The results showed that when only DMI from the basal diet was considered, there was a linear reduction (P<.01) in DMI and a linear improvement (P<.01) in the gain:feed ratio with no effect on daily gain as thin stillage DM concentration increased. No differences were detected in DMI or efficiency of gain when total DMI (basal diet and thin stillage) was considered. Carcass traits indicated a trend toward increased (P<.06) carcass fat with increasing thin stillage DM concentration. Results of Trial 2 indicated a linear improvement (P<.05) in apparent digestibility of DM, CP, NDF, and energy of the total diet (basal diet and thin stillage) as thin stillage DM concentration increased. We concluded that supplementing growing and finishing cattle with thin stillage reduced the amount of the basal diet required for gain and improved nutrient utilization.

Intradermal immunization with a bovine herpesvirus-1 DNA vaccine induces protective immunity in cattle

Although intramuscular (i.m.) injection of DNA encoding glycoprotein D (gD) of bovine herpesvirus-1 (BHV-1) induces immune responses in cattle, this route of delivery is inefficient. Here we assessed three parameters that may enhance the efficacy of a gD DNA vaccine in cattle. First, the immune response generated by i.m. injected plasmid expressing a secreted form of gD (tgD) was determined and found to be very similar in magnitude to the response induced by gD-expressing plasmid. Secondly, gD- and tgD-expressing plasmids were administered by intradermal (i.d.) immunization, which resulted in a superior immune response to the secreted form, but no improvement in the response to the membrane-associated form. However, the form of gD used for immunization did not influence the immunoglobulin subtype, the ratio of antigen-specific IgG1 to IgG2 being approximately 4:1. Finally, the effect of promoter strength was assessed by replacing the Rous sarcoma virus (RSV) promoter, which was used in the original experiments, with the human cytomegalovirus immediate early promoter and first intron A (HCMV/IA). Although upon transfection in vitro the HCMV/IA promoter appeared to be stronger than the RSV promoter, there was only a 2-fold higher antibody response in vivo upon i.d. injection of cattle. Protection against virus challenge was obtained in the calves immunized i.d. with tgD-encoding plasmid, as shown by a significant reduction in weight loss, virus excretion, temperature response and clinical disease. No significant protection was observed in the animals vaccinated i.d. with the gD-expressing plasmid, which correlates with the lower level of immunity pre-challenge.

Acceleration of the maturation of oligodendroblasts into oligodendrocytes and enhancement of their myelinogenic properties by a chemically defined medium

Because of the importance of oligodendrocytes (OL) in forming and maintaining myelin in the CNS and the fact that the remyelination in the CNS is very limited in contrast to the peripheral nervous system, we investigated the effect of a chemically defined medium OLDEM, previously characterized by the maintenance of mature myelinating OL, on oligodendroblasts (or OL progenitors) in culture. The effect of each component of this medium as well as different combinations of them were also examined. Cultures were examined at different developmental stages immunocytochemically for developmental markers, such as transferrin, sulfatides, myelin basic protein and proteolipid protein. OLDEM accelerated the appearance of developmental markers and concomitant morphological changes. Furthermore, myelin-specific enzymes such as glycerophosphorylcholine phosphodiesterase; p-nitro-phenolphosphocholine phosphodiesterase; 2'3'-cyclic nucleotide 3'-phosphodiesterase and UDP galactose: ceramide galactosyltransferase had enzymatic activities similar to values found in pure myelin, indicating that OLDEM allows the optimal expression of myelin-related genes. The effect of each OLDEM constituent was evaluated by immunocytochemistry and by measurement of enzymatic activities. With each single additive or multiple combinations, oligodendrocytes displayed different degrees of maturation. Deletion of selenium, glucose, and galactose severely affected cell survival as well as enzymes expression in young cultures. However, older cultures were more resistant to these deletions. Putrescine and insulin did not cause such effects on survival, but their absence affected cell maturation. None of the OLDEM additives individually supported survival and/or maturation. Enzyme assays performed on isolated myelin-like membranes or the cells soma revealed a redistribution of the activity between these fractions as the cell matured. The biological role of each of these constituents on the maturation of the oligodendroglial cells is discussed. These observations indicate that OLDEM constituents have a powerful effect on OL progenitor maturation, and membrane formation. This medium will be used for investigating the remyelination potential of adult OL progenitors.

Phospholipase D activity of rat brain neuronal nuclei

Phospholipase D activity of rat brain neuronal nuclei, measured with exogenous phosphatidylcholine as substrate, was characterized. The measured activity of neuronal nuclei was at least 36-fold greater than the activity in glia nuclei. The pH optimum was 6.5, and unsaturated but not saturated fatty acids stimulated the enzyme. The optimal concentration of sodium oleate for stimulation of the enzyme activity was 1.2 mM in the presence of 0.75 mM phosphatidylcholine. This phospholipase D activity was cation independent. In the absence of NaF, used as a phosphatidic acid phosphatase inhibitor, the principal product was diglyceride; whereas in the presence of NaF, the principal product was phosphatidic acid. The phospholipase D, in addition to having hydrolytic activity, was able to catalyze a transphosphatidylation reaction. Maximum phosphatidylethanol formation was seen with 0.2-0.3 M ethanol. GTPgammaS, ATPgammaS, BeF2, AIF3, phosphatidic acid, and phosphatidylethanol inhibited the neuronal nuclei phospholipase D activity. The addition of the cytosolic fraction of brain, liver, kidney, spleen, and heart to the incubation mixtures resulted in inhibition of the phospholipase D activity. Phospholipase D activity was detectable in nuclei prepared from rat kidney, spleen, heart, and liver.

Efficacy of an experimental BHV-1 subunit gIV vaccine in beef calves challenged with BHV-1 in aerosol

Thirty-six beef calves were used to test the efficacy of an experimental truncated BHV-1 glycoprotein (tgIV) vaccine. Calves from 1 source and +/- 1 mo of age were randomly divided into 4 groups: 1) control (adjuvant VSA3), 2) vaccinated with tgIV at 3 and 4 mo of age, 3) vaccinated with tgIV at 3 and 7 mo of age, or 4) vaccinated with tgIV at 6 and 7 mo of age. Calves were challenged with BHV-1 in aerosol (strain 108) at 7 1/2 mo of age. Prior to challenge, serum neutralizing (SN) antibody titers to BHV-1 were significantly (P < 0.05) higher in all vaccinated calves than in controls. Calves vaccinated at 3 and 7, or 6 and 7, mo of age had significantly (P < 0.05) higher SN antibody and nasal antibody titers to BHV-1 and ELISA (enzyme linked immunosorbent assay) titers to gIV at prechallenge than those vaccinated at 3 and 4 mo of age or controls. Postchallenge nasal shedding of BHV-1 occurred only in controls and those vaccinated at 3 and 4 mo of age. Control calves lost significantly (P < 0.05) more weight and had higher sick scores after challenge than those vaccinated at 3 and 7, or at 6 and 7, mo of age. There were strong correlations (P < 0.001) between antibody titers, virus shedding, and sickness.

Operative stabilization of pediatric femur fractures

Femur fractures represent approximately 1.7% of all pediatric bony injuries. Most femur fractures were treated nonoperatively prior to the early 1980s. Recent refinements in the operative techniques used to treat pediatric femur fracture have led to a reduction in the use of traction and casting treatment methods.

Phospholipase D activity of isolated rat brain plasma membranes

With [14C]oleate-labeled phosphatidylcholine as a substrate for phospholipase D the hydrolytic activity was measured by phosphatidic acid formation and the transphosphatidylation activity was measured by the phosphatidylethanol formed in the presence of ethanol. The pH optimum was 6.5 with dimethylglutarate as the buffer. EGTA inhibited the transphosphatidylation activity to a greater extent than the hydrolytic activity. In contrast CaCl2, BaCl2, MgCl2 and SrCl2 stimulated the hydrolytic activity without effecting the transphosphatidylation activity. BeCl2 another member of the group IIa transition metals was a very potent inhibitor of both the hydrolytic and transphophatidylation activity. GTP gamma S, an activator of G protein-mediated events, was an inhibitor of both activities.

The predictive value of pelvimetry in beef cattle

To elucidate reasons for failure of pelvimetry to predict dystocia, we collected data from 1146 heifers and 210 cows in five beef cow herds in Saskatchewan. We assessed the reliability of pelvic area measurements, the generalizability of findings, various modifications of the technique, and the statistical association between pelvic area measurements and dystocia. The repeatability (kappa) of pelvic area measurements between and within veterinarians for the Rice and Krautmann pelvimeters were low to moderate, indicating pelvic area measurements were imprecise. The positive predictive values and sensitivities of pelvic area measurements were consistently poor across herds, years of study, breeds of heifers, times of measurement, various pelvic area cut-off points, and sires. Various modifications of the technique, including pelvic area/calf birth weight ratios, pelvic area/heifer weight ratios, and Ko's calving prediction equation were also poor on-farm tests for predicting dystocia. Although the mean pelvic area in heifers with dystocia was smaller than those without dystocia, there was a large overlap in the distribution of their measurements. Far too many heifers with a small pelvic area had no dystocia (false positives) and far too many heifers with a large pelvic area had dystocia (false negatives) for pelvimetry to be useful. We conclude there is little evidence to justify the continued use of pelvimetry as an on-farm test to reduce dystocia in beef cattle.

Comparative serological response in calves to eight commercial vaccines against infectious bovine rhinotracheitis, parainfluenza-3, bovine respiratory syncytial, and bovine viral diarrhea viruses

A field trial was conducted to compare the serological responses in calves to eight commercial vaccines against infectious bovine rhinotracheitis virus (IBRV), parainfluenza-3 virus (PI3V), bovine respiratory syncytial virus (BRSV), and/or bovine viral diarrhea virus (BVDV). Calves given IBRV, P13V, BRSV, and BVDV vaccines had significantly higher antibodies to these viruses than unvaccinated controls; however, serological responses to killed BVDV vaccines were low. Calves with preexisting antibodies to IBRV, PI3V, BRSV, and the Singer strain of BVDV had lower seroconversion rates following vaccination than calves that were seronegative initially.Serological responses in calves to IBRV, PI3V, BRSV, and BVDV differed among various commercial vaccines. Antibody titers to IBRV were higher in calves vaccinated with modified-live IBRV vaccines than in those vaccinated with killed IBRV vaccines. Following double vaccination with modified-live IBRV and PI3V vaccines, seroconversion rates and antibody titers to IBRV and PI3V were higher in calves vaccinated intramuscularly than in those vaccinated intranasally. Calves given Cattlemaster 4 had significantly higher titers to BRSV and PI3V, and lower titers to BVDV, than calves given Cattlemaster 3, suggesting that the addition of BRSV to Cattlemaster 4 caused some interaction among antigens.

Sphingosine and unsaturated fatty acids modulate the base exchange enzyme activities of rat brain membranes

The base exchange enzymes catalyze the incorporation of L-serine, ethanolamine and choline into their corresponding phospholipids. The L-serine base enzyme activity was increased 120% by 0.1 mM sphingosine. There was a modest increase of the ethanolamine base exchange enzyme activity but the choline base exchange enzyme activity was unaffected. Na-arachadonate, Na-oleate and Na-linolenate at 0.2 mM concentration increased the activity of the L-serine and ethanolamine base exchange enzymes but inhibited the choline base exchange enzyme activity. A model is proposed suggesting that modulations of the L-serine base exchange enzyme may participate in the regulation of the calcium phospholipid-dependent protein kinase C.

An unusual phosphodiesterase activity towards p-nitrophenylphosphorylcholine present in rat brain membranes

A phosphodiesterase activity present in rat brain membranes has been examined utilizing p-nitrophenylphosphorylcholine as the substrate. This enzyme activity has a pH optimum of 8.5, is stimulated by a variety of free fatty acids, requires either Zn+2 or Ca+2 and is relatively stable to heating at 75 degrees C for 7.5 minutes. These properties appear to distinguish this particular activity from those previously reported for alkaline phosphatase, nonspecific phosphodiesterase, phosphodiesterases I and II, lecithinase, and sphingomyelinase.

Regulation of the choline, ethanolamine and serine base exchange enzyme activities of rat brain microsomes by phosphorylation and dephosphorylation

The base exchange enzyme activities of rat brain microsomes were estimated subsequent to preincubations under conditions for either protein phosphorylation or dephosphorylation. Quantitatively the choline base exchange activity was most affected by these treatments. Exposure of the microsomes to alkaline phosphatase resulted in a decrease of all three base exchange activities. Pretreatment with a cAMP-dependent protein kinase resulted in increases of all 3 enzyme activities. Conditions favoring protein kinase C phosphorylation resulted in stimulation of the choline base exchange activity.