GSK2245035, a TLR7 agonist, Does Not Increase Pregnancy Loss in Cynomolgus Monkeys

GSK2245035, a small molecule Toll-like Receptor 7 (TLR7) agonist developed for immunomodulatory treatment for allergic airways disease, aimed to reduce Th2 and enhance Th1/Treg responses to aeroallergens via the local induction of type I interferons (IFNs). GSK2245035 demonstrated selectivity for potent release of type I IFNs compared to TNF-α and IL-6, with dose dependent increases in the interferon inducible chemokine, IP-10, in the nasal compartment. Implantation and parturition require pro-inflammatory processes including IFNs, Interferon Stimulated Genes, TNFα and IP-10 while pregnancy requires immune regulation to maintain maternal fetal immune tolerance, and recombinant type I IFNs induced abortions in monkeys. Due to its mechanism of action, GSK2245035 was studied at pharmacologically and clinically relevant doses in a monkey pregnancy model. Monkeys received 0, 3 or 30 ng/kg/week GSK2245035 intranasally once weekly, from Day 20 postcoitum through Day 63 postpartum. Although systemic IFN-α and IP-10 levels were approximately 14.8 or 40 -fold (respectively) above predose levels at 3 or 30 ng/kg/week, respectively, there were no effects on pregnancy and infant outcome. Non-adverse effects included increased incidence of nasal discharge, increased maternal body temperature at 30 ng/kg/week and dose-dependent increases in maternal IP-10 and IFN-α and decreased infant anti-KLH IgM and IgG titers following KLH immunization at ≥3 ng/kg/week, relative to controls. Potentially, lower IFN-α and IP-10 levels as well as once-weekly intranasal dosing vs daily subcutaneous or intramuscular dosing with recombinant type I IFNs could explain the lack of pregnancy effects; however, there was an undesired impact on offspring immune function.

Approach for gait analysis in persons with limb loss including residuum and prosthesis socket dynamics

Musculoskeletal modeling and marker-based motion capture techniques are commonly used to quantify the motions of body segments, and the forces acting on them during human gait. However, when these techniques are applied to analyze the gait of people with lower limb loss, the clinically relevant interaction between the residual limb and prosthesis socket is typically overlooked. It is known that there is considerable motion and loading at the residuum-socket interface, yet traditional gait analysis techniques do not account for these factors due to the inability to place tracking markers on the residual limb inside of the socket. In the present work, we used a global optimization technique and anatomical constraints to estimate the motion and loading at the residuum-socket interface as part of standard gait analysis procedures. We systematically evaluated a range of parameters related to the residuum-socket interface, such as the number of degrees of freedom, and determined the configuration that yields the best compromise between faithfully tracking experimental marker positions while yielding anatomically realistic residuum-socket kinematics and loads that agree with data from the literature. Application of the present model to gait analysis for people with lower limb loss will deepen our understanding of the biomechanics of walking with a prosthesis, which should facilitate the development of enhanced rehabilitation protocols and improved assistive devices.

e-TC: Development and pilot testing of a web-based intervention to reduce anxiety and depression in survivors of testicular cancer

e-TC is an online intervention designed to address common psychosocial concerns of testicular cancer survivors. It aims to reduce anxiety, depression and fear of cancer recurrence by providing evidence-based information and psychological intervention. This paper details the development and pilot testing of e-TC. During pilot testing, 25 men (with varying psychological profiles) who had completed treatment for testicular cancer, 6 months to 5 years ago (which had not recurred), used e-TC over a 10-week period and provided quantitative and qualitative feedback on the feasibility and acceptability of the programme. Six men also completed a qualitative interview to provide detailed feedback on their experiences using e-TC. Fourteen men (56%) completed at least 80% of the programme. Participants reported a high level of satisfaction with the programme. Men's limited time was a barrier to programme use and completion, and participants suggested that men with a more recent diagnosis and a higher level of distress may be more likely to engage with the programme. e-TC appears to be a feasible and acceptable online intervention for survivors of testicular cancer. Findings from this study are currently being used to refine e-TC and guide the design of a larger efficacy study.

iCanADAPT Early protocol: randomised controlled trial (RCT) of clinician supervised transdiagnostic internet-delivered cognitive behaviour therapy (iCBT) for depression and/or anxiety in early stage cancer survivors -vs- treatment as usual

BACKGROUND

This RCT with two parallel arms will evaluate the efficacy of an internet-delivered transdiagnostic cognitive behavioural therapy (iCBT) intervention for the treatment of clinical depression and/or anxiety in early stage cancer survivors.

METHODS/DESIGN

Early stage cancer survivors will be recruited via the research arm of a not-for-profit clinical research unit and randomised to an intervention (iCBT) group or a 'treatment as usual' (TAU) control group. The minimum sample size for each group is 45 people (assuming effect size > 0.6, power of 80%, and alpha at .05), but 10% more will be recruited to account for attrition. A solitary or cumulative diagnosis(es) of Major Depressive Episode (current), Generalised Anxiety Disorder, Illness Anxiety Disorder, Panic Disorder, Agoraphobia, and/or Adjustment disorder will be determined using modules from the Anxiety Disorders Interview Schedule for DSM-5. Depression and anxiety levels with be measured via the total score of the Hospital Anxiety and Depression scale (HADS-T), the primary outcome measure. Secondary measures will include the Kessler 10 to measure general distress, the Fear of Cancer Recurrence Inventory (FCRI) to measure the specific fear of cancer recurrence and the Functional Assessment of Cancer Therapy, General Version 4 (FACT-G) for self-report of physical, social, emotional and functional well-being. iCBT participants will complete the measures before lessons 1 and 5, at post-treatment and at 3-month follow-up. The TAU group will complete similar measures at weeks 1, 8 and 16 of the waiting period. Program efficacy will be determined using intent-to-treat mixed models. Maintenance of gains will be assessed at 3-month follow-up. Mediation analyses using PROCESS will be used to examine the association between change in depressive and anxious symptoms over time and changes in FCRI and FACT-G QOL in separate analysis.

DISCUSSION

This is the first RCT looking at iCBT specifically for clinical depression and/or anxiety in a cancer population. Findings will help to direct the role of iCBT in streamlined psycho-social care pathways.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry: ACTRN12616000231448, registered 19th February 2016 ( www.anzctr.org.au ). This trial protocol is in compliance with the Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) guidelines.

Control Points To Reduce Movement of Central Nervous System Tissue during Beef Slaughter

Consumption of central nervous system tissue (CNST) from cattle with bovine spongiform encephalopathy (BSE) is thought to cause the human neurological disease, variant Creutzfeldt-Jacob disease. To identify points of cross-contamination of beef carcasses with CNST, 55 young beef cattle were slaughtered and processed through a federally inspected multispecies abattoir. The objectives of this study were to evaluate CNST spread following the placement of a plug in the penetration site of the skull after captive bolt stunning, to evaluate cross-contamination of carcasses before and after splitting, to compare the effects of hot water pasteurization (84°C for 10 s) versus cold water wash (10°C for 30 s) for reducing CNST on the carcass, and to examine other possible sources of cross-contamination in the abattoir. Results indicated that the use of a plastic plug reduced CNST contamination near the bolt penetration site. This study also confirmed that carcass splitting resulted in an increase in CNST contamination at various areas of the carcass. Hot water pasteurization appeared to be an effective means of removing CNST contamination from carcasses in most of the areas sampled.

Heterogeneity of HIV incidence: a comparative analysis between fishing communities and in a neighbouring rural general population, Uganda, and implications for HIV control

OBJECTIVES

To describe HIV heterogeneity in rural Uganda using incidence data collected between January 2012 and December 2014 among fishing cohort (FC) and in an adjacent rural general population cohort (GPC).

METHODS

In the FC, eligible HIV high-risk adults aged 18+ years were enrolled, followed and HIV tested every 3 months. Demographic and sexual behaviour data were also collected. The GPC, approximately 47 km away from the FC, was followed through annual surveys, and sociodemographic and behavioural data collected. A subset of GPC with comparable risk profiles to the FC was selected. We presented sociodemographic and risk profiles and also computed stratified HIV incidence. Cox regression was used to assess factors associated with HIV incidence.

RESULTS

Overall HIV incidence was higher in the FC than in the 'high-risk' GPC, 6.04 and 0.56 per 100 person years at risk, respectively, with a rate ratio (RR) of 10.83 (95% CI 6.11 to 19.76). This was higher among those aged 18-24 years, unmarried and those with more than two sex partners in the past year, RR of 15.44, 22.99 and 19.29, respectively. In the FC, factors associated with high incidence in multivariate analysis were duration in the community and unprotected sex. The factors in the GPC were ethnicity, marital status and duration in the community.

CONCLUSIONS

We have observed a substantial heterogeneity in HIV incidence. The high incidence in fishing communities is contributing greatly to the overall HIV burden in Uganda, and thus urgent combination prevention efforts are needed towards national goal to reduce HIV epidemic.

Physical symptoms, coping styles and quality of life in recurrent ovarian cancer: a prospective population-based study over the last year of life

OBJECTIVE

The aim of this study was to describe the trajectory of physical symptoms, coping styles and quality of life (QoL) and the relationship between coping and QoL over the last year of life in women with recurrent ovarian cancer.

METHODS

The patient cohort were women recruited to the Australian Ovarian Cancer Study who subsequently experienced recurrent, invasive ovarian cancer and completed at least one psychosocial assessment (optimism, minimisation, hopelessness/helplessness, QoL) during the last year of life (n=217).

RESULTS

QoL declined sharply from six months before death. Lack of energy was the most prevalent symptom over three measurement periods (67-92%) and also the most severe. Anorexia (36-55%), abdominal swelling (33-58%), nausea (26-47%) and pain (26-43%) all increased in prevalence and severity towards the end of life. Higher optimism (p=0.009), higher minimisation (p=0.003) and lower helplessness/hopelessness (p=0.03) at baseline were significant predictors of subsequent higher QoL.

CONCLUSIONS

Progressive deterioration in quality of life may be an indicator of death within about six months and therefore should be an important consideration in decisions about subsequent treatment. Coping styles which independently predicted subsequent changes in QoL could potentially be targeted by interventions to minimise worsening QoL.

Choosing between the EORTC QLQ-C30 and FACT-G for measuring health-related quality of life in cancer clinical research: issues, evidence and recommendations

BACKGROUND

This review aims to assist cancer clinical researchers in choosing between the two most widely used measures of cancer-specific health-related quality of life: the European Organisation for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and Functional Assessment of Cancer Therapy-General (FACT-G).

MATERIALS AND METHODS

Information on QLQ-C30 and FACT-G content, scale structure, accessibility and availability was collated from websites and manuals. A systematic review was undertaken to identify all articles reporting on psychometric properties and information to assist interpretability. Evidence for reliability, validity and responsiveness was rated using a standardised checklist. Instrument properties were compared and contrasted to inform recommendations.

RESULTS

Psychometric evidence does not recommend one questionnaire over the other in general. However, there are important differences between the scale structure, social domains and tone that inform choice for any particular study.

CONCLUSIONS

Where research objectives are concerned with the impact of a specific tumour type, treatment or symptom, choice should be guided by the availability, content, scale structure and psychometric properties of relevant European Organisation for the Research and Treatment of Cancer versus Functional Assessment of Chronic Illness Therapy modules. Because the FACT-G combines symptoms and concerns within each scale, individual items should always be reviewed within the context of specific research objectives. Where these issues are indecisive, researchers are encouraged to use an algorithm at the end of the current article.

Inhibition of cleavage of a plant viral polyprotein by an inhibitor activity present in wheat germ and cowpea embryos

In rabbit reticulocyte lysate, the bottom component RNA of cowpea mosaic virus directs the synthesis of a 200,000-molecular-weight precursor protein (200K protein) that is cleaved during synthesis by a reticulocyte enzyme to form a 32K protein and a 170K protein. Cleavage of the 200K protein was found to be effectively inhibited by inhibitor activity in wheat germ and cowpea embryo extracts. The inhibitor was nondialyzable, precipitatable by ammonium sulfate, and partially stable at high temperatures. The activity appeared to be specific in that it caused no inhibition of the secondary cleavage reactions (cleavage of the 170K protein) at concentrations that were sufficient to cause complete inhibition of the primary cleavage reaction (cleavage of the 200K protein).

Screening for genital and anorectal sexually transmitted infections in HIV prevention trials in Africa

OBJECTIVES

To demonstrate the value of routine, basic sexually transmitted infection (STI) screening at enrolment into an HIV-1 vaccine feasibility cohort study and to highlight the importance of soliciting a history of receptive anal intercourse (RAI) in adults identified as "high risk".

METHODS

Routine STI screening was offered to adults at high risk of HIV-1 upon enrolment into a cohort study in preparation for HIV-1 vaccine trials. Risk behaviours and STI prevalence were summarised and the value of microscopy assessed. Associations between prevalent HIV-1 infection and RAI or prevalent STI were evaluated with multiple logistic regression.

RESULTS

Participants had a high burden of untreated STI. Symptom-directed management would have missed 67% of urethritis cases in men and 59% of cervicitis cases in women. RAI was reported by 36% of male and 18% of female participants. RAI was strongly associated with HIV-1 in men (adjusted odds ratio (aOR) 3.8; 95% CI 2.0 to 6.9) and independently associated with syphilis in women (aOR 12.9; 95% CI 3.4 to 48.7).

CONCLUSIONS

High-risk adults recruited for HIV-1 prevention trials carry a high STI burden. Symptom-directed treatment may miss many cases and simple laboratory-based screening can be done with little cost. Risk assessment should include questions about anal intercourse and whether condoms were used. STI screening, including specific assessment for anorectal disease, should be offered in African research settings recruiting participants at high risk of HIV-1 acquisition.

Genetic and phenotypic relationships of feed intake and measures of efficiency with growth and carcass merit of beef cattle1

Feed intake and efficiency of growth are economically important traits of beef cattle. This study determined the relationships of daily DMI, feed:gain ratio [F:G, which is the reciprocal of the efficiency of gain (G:F) and therefore increases as the efficiency of gain decreases and vice versa, residual feed intake (RFI), and partial efficiency of growth (efficiency of ADG, PEG) with growth and carcass merit of beef cattle. Residual feed intake was calculated from phenotypic regression (RFIp) or genetic regression (RFIg) of ADG and metabolic BW on DMI. An F1 half-sib pedigree file containing 28 sires, 321 dams, and 464 progeny produced from crosses between Alberta Hybrid cows and Angus, Charolais, or Alberta Hybrid bulls was used. Families averaged 20 progeny per sire (range = 3 to 56). Performance, ultrasound, and DMI data was available on all progeny, of which 381 had carcass data. Phenotypic and genetic parameters were obtained using SAS and ASREML software, respectively. Differences in RFIp and RFIg, respectively, between the most and least efficient steers (i.e., steers with the lowest PEG) were 5.59 and 6.84 kg of DM/d. Heritabilities for DMI, F:G, PEG, RFIp, and RFIg were 0.54 +/- 0.15, 0.41 +/- 0.15, 0.56 +/- 0.16, 0.21 +/- 0.12, and 0.42 +/- 0.15, respectively. The genetic (r = 0.92) and phenotypic (r = 0.97) correlations between RFIp and RFIg indicated that the 2 indices are very similar. Both indices of RFI were favorably correlated phenotypically (P < 0.001) and genetically with DMI, F:G, and PEG. Residual feed intake was tendentiously genetically correlated with ADG (r = 0.46 +/- 0.45) and metabolic BW (r = 0.27 +/- 0.33), albeit with high SE. Genetically, RFIg was independent of ADG and BW but showed a phenotypic correlation with ADG (r = -0.21; P < 0.05). Daily DMI was correlated genetically (r = 0.28) and phenotypically (r = 0.30) with F:G. Both DMI and F:G were strongly correlated with ADG (r > 0.50), but only DMI had strong genetic (r = 0.87 +/- 0.10) and phenotypic (r = 0.65) correlations with metabolic BW. Generally, the phenotypic and genetic correlations of RFI with carcass merit were not different from zero, except genetic correlations of RFI with ultrasound and carcass LM area and carcass lean yield and phenotypic correlations of RFI with backfat thickness (P < 0.01). Daily DMI had moderate to high phenotypic (P < 0.01) and genetic correlations with all the ultrasound and carcass traits. Depending on how RFI technology is applied, adjustment for body composition in addition to growth may be required to minimize the potential for correlated responses to selection in cattle.

Genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit of feedlot cattle1

Leptin is the hormone product of the obese gene that is synthesized and predominantly expressed by adipocytes. This study estimated the genetic variation in serum leptin concentration and evaluated the genetic and phenotypic relationships of serum leptin concentration with performance, efficiency of gain, and carcass merit. There were 464 steers with records for serum leptin concentration, performance, and efficiency of gain and 381 steers with records for carcass traits. The analyses included a total of 813 steers, including those without phenotypic records. Phenotypic and genetic parameter estimates were obtained using SAS and ASREML, respectively. Serum leptin concentration was moderately heritable (h2 = 0.34 +/- 0.13) and averaged 13.91 (SD = 5.74) ng/mL. Sire breed differences in serum leptin concentration correlated well with breed differences in body composition. Specifically, the serum leptin concentration was 20% greater in Angus-sired steers compared with Charolais-sired steers (P < 0.001). Consequently, ultrasound backfat (27%), carcass 12th-rib fat (31%), ultrasound marbling (14%), and carcass marbling (15%) were less in Charolais- than Angus-sired steers (P < 0.001). Conversely, carcass LM area (P = 0.05) and carcass lean meat yield (P < 0.001) were greater in Charolais- compared with Angus-sired steers. Steers with greater serum leptin concentration also had greater DMI (P < 0.001), greater residual feed intake (P = 0.04), and partial efficiency of growth (P = 0.01), but did not differ in feed conversion ratio (P > 0.10). Serum leptin concentration was correlated phenotypically with ultrasound backfat (r = 0.41; P < 0.001), carcass 12th-rib fat (r = 0.42; P < 0.001), ultrasound marbling (r = 0.25; P < 0.01), carcass marbling (r = 0.28; P < 0.01), ultrasound LM area (r = -0.19; P < 0.01), carcass LM area (r = -0.17; P < 0.05), lean meat yield (r = -0.38; P < 0.001), and yield grade (r = 0.32; P < 0.001). The corresponding genetic correlations were generally greater than the phenotypic correlations and included ultrasound backfat (r = 0.76 +/- 0.19), carcass 12th-rib fat (r = 0.54 +/- 0.23), ultrasound marbling (r = 0.27 +/- 0.22), carcass marbling (r = 0.76 +/- 0.21), ultrasound LM area (r = -0.71 +/- 0.19), carcass LM area (r = -0.75 +/- 0.20), lean meat yield (r = -0.59 +/- 0.22), and yield grade (r = 0.39 +/- 0.26). Serum leptin concentration can be a valuable tool that can be incorporated into appropriate selection programs to favorably improve the carcass merit of cattle.

Genetic and phenotypic relationships of feeding behavior and temperament with performance, feed efficiency, ultrasound, and carcass merit of beef cattle

Feeding behavior and temperament may be useful in genetic evaluations either as indicator traits for other economically relevant traits or because the behavior traits may have a direct economic value. We determined the variation in feeding behavior and temperament of beef cattle sired by Angus, Charolais, or Hybrid bulls and evaluated their associations with performance, efficiency, and carcass merit. The behavior traits were daily feeding duration, feeding head down (HD) time, feeding frequency (FF), and flight speed (FS, as a measure of temperament). A pedigree file of 813 animals forming 28 paternal half-sib families with about 20 progeny per sire was used. Performance, feeding behavior, and efficiency records were available on 464 animals of which 381 and 302 had records on carcass merit and flight speed, respectively. Large SE reflect the number of animals used. Direct heritability estimates were 0.28 +/- 0.12 for feeding duration, 0.33 +/- 0.12 for HD, 0.38 +/- 0.13 for FF, and 0.49 +/- 0.18 for FS. Feeding duration had a weak positive genetic (r(g)) correlation with HD (r(g) = 0.25 +/- 0.32) and FS (r(g) = 0.42 +/- 0.26) but a moderate negative genetic correlation with FF (r(g) = -0.40 +/- 0.30). Feeding duration had positive phenotypic (r(p)) and genetic correlations with DMI (r(p) = 0.27; r(g) = 0.56 +/- 0.20) and residual feed intake (RFI; r(p) = 0.49; r(g) = 0.57 +/- 0.28) but was unrelated phenotypically with feed conversion ratio [FCR; which is the reciprocal of the efficiency of growth (G:F)]. Feeding duration was negatively correlated with FCR (r(g) = -0.25 +/- 0.29). Feeding frequency had a moderate to high negative genetic correlation with DMI (r(g) = -0.74 +/- 0.15), FCR (r(g) = -0.52 +/- 0.21), and RFI (r(g) = -0.77 +/- 0.21). Flight speed was negatively correlated phenotypically with DMI (r(p) = -0.35) but was unrelated phenotypically with FCR or RFI. On the other hand, FS had a weak negative genetic correlation with DMI (r(g) = -0.11 +/- 0.26), a moderate genetic correlation with FCR (r(g) = 0.40 +/- 0.26), and a negative genetic correlation with RFI (r(g) = -0.59 +/- 0.45). The results indicate that behavior traits may contribute to the variation in the efficiency of growth of beef cattle, and there are potential correlated responses to selection to improve efficiency. Feeding behavior and temperament may need to be included in the definition of beef cattle breeding goals, and approaches such as the culling of unmanageable cattle and the introduction of correct handling facilities or early life provision of appropriate experiences to improve handling will be useful.

Relationships of feedlot feed efficiency, performance, and feeding behavior with metabolic rate, methane production, and energy partitioning in beef cattle

Residual feed intake (RFI) is the difference between the actual and expected feed intake of an animal based on its BW and growth rate over a specified period. The biological mechanisms underlying the variation in feed efficiency in animals with similar BW and growth rate are not well understood. This study determined the relationship of feedlot feed efficiency, performance, and feeding behavior with digestion and energy partitioning of 27 steers. The steers were selected from a total of 306 animals based on their RFI following feedlot tests at the University of Alberta Kinsella Research Station. Selected steers were ranked into high RFI (RFI > 0.5 SD above the mean, n = 11), medium RFI (RFI +/- 0.5 SD above and below the mean, n = 8), and low RFI (RFI < -0.5 SD below the mean, n = 8). The respective BW +/- SD for the RFI groups were 495.6 +/- 12.7, 529.1 +/- 18.6, and 501.2 +/- 15.5 kg. Digestibility and calorimetry trials were performed on a corn-or barley-based concentrate diet in yr 1 and 2, respectively, at 2.5 x maintenance requirements. Mean DMI (g/kg of BW(0.75)) during the measurements for high-, medium-, and low-RFI groups, respectively, were 82.7 +/- 2.0, 78.8 +/- 2.6, and 81.8 +/- 2.5 and did not differ (P > 0.10). Residual feed intake was correlated with daily methane production and energy lost as methane (r = 0.44; P < 0.05). Methane production was 28 and 24% less in low-RFI animals compared with high- and medium-RFI animals, respectively. Residual feed intake tended to be associated (P < 0.10) with apparent digestibilities of DM (r = -0.33) and CP (r = -0.34). The RFI of steers was correlated with DE (r = -0.41; P < 0.05), ME (r = -0.44; P < 0.05), heat production (HP; r = 0.68; P < 0.001), and retained energy (RE; r = -0.67; P < 0.001; energy values are expressed in kcal/kg of BW(0.75)). Feedlot partial efficiency of growth was correlated (P < 0.01) with methane production (r = -0.55), DE (r = 0.46), ME (r = 0.49), HP (r = -0.50), and RE (r = 0.62). With the exception of HP (r = 0.37; P < 0.05), feed conversion ratio was unrelated to the traits considered in the study. Feeding duration was correlated (P < 0.01) with apparent digestibility of DM (r = -0.55), CP (r = -0.47), methane production (r = 0.51), DE (r = -0.52), ME (r = -0.55), and RE (r = -0.60). These results have practical implications for the selection of animals that eat less at a similar BW and growth rate and for the environmental sustainability of beef production.

Different measures of energetic efficiency and their phenotypic relationships with growth, feed intake, and ultrasound and carcass merit in hybrid cattle1

Residual feed intake (RFI) has been proposed as an index for determining beef cattle energetic efficiency. Although the relationship of RFI with feed conversion ratio (FCR) is well established, little is known about how RFI compares to other measures of efficiency. This study examined the phenotypic relationships among different measures of energetic efficiency with growth, feed intake, and ultrasound and carcass merit of hybrid cattle (n = 150). Dry matter intake, ME intake (MEI), ADG, metabolic weight (MWT), and FCR during the test averaged 10.29 kg/d (SD = 1.62), 1,185.45 kJ/(kg0.75 x d) (SD = 114.69), 1.42 kg/d (SD = 0.25), 86.67 kg0.75 (SD = 10.21), and 7.27 kg of DM/kg of gain (SD = 1.00), respectively. Residual feed intake averaged 0.00 kg/d and ranged from -2.25 kg/d (most efficient) to 2.61 kg/d (least efficient). Dry matter intake (r = 0.75), MEI (r = 0.83), and FCR (r = 0.62) were correlated with RFI (P < 0.001) and were higher for animals with high (>0.5 SD) RFI vs. those with medium (+/-0.5 SD) or low (<0.5 SD) RFI (P < 0.001). Partial efficiency of growth (PEG; energetic efficiency for ADG) was correlated with RFI (r = -0.89, P < 0.001) and was lower (P < 0.001) for high- vs. medium- or low-RFI animals. However, RFI was not related to ADG (r = -0.03), MWT (r = -0.02), relative growth rate (RGR; growth relative to instantaneous body size; r = -0.04), or Kleiber ratio (KR; ADG per unit of MWT; r = -0.004). Also, DMI was correlated (P < 0.01) with ADG (r = 0.66), MWT (r = 0.49), FCR (r = 0.49), PEG (r = -0.52), RGR (r = 0.18), and KR (r = 0.36). Additionally, FCR was correlated (P < 0.001) with ADG (r = -0.63), PEG (r = -0.83), RGR (r = -0.75), and KR (r = -0.73), but not with MWT (r = 0.07). Correlations of measures of efficiency with ultrasound or carcass traits generally were not different from zero except for correlations of RFI, FCR, and PEG, respectively, with backfat gain (r = 0.30, 0.20, and -0.30), ultrasound backfat (r = 0.19, 0.21, and -0.25), grade fat (r = 0.25, 0.19, and -0.27), lean meat yield (r = -0.22, -0.18, and 0.24), and yield grade (r = 0.28, 0.24, and -0.25). These phenotypic relationships indicate that, compared with other measures of energetic efficiency, RFI should have a greater potential to improve overall production efficiency and PEG above maintenance, and lead to minimal correlated changes in carcass merit without altering the growth and body size of different animals.

Seasonal herbage dynamics on Aspen Parkland landscapes in central Alberta

We evaluated the temporal dynamics of herbage biomass and protein within riparian meadows and upland grasslands of native Aspen Parkland rangeland to understand the contribution of each to lives tock foraging. For the growing season monitored, meadows were greater in forage yield and crude protein (P < 0.05), leading to important implications for sustainable livestock production and rangeland conservation. Key words: Crude protein, forage production, riparian meadow, upland grassland

Feeding value of peas for backgrounding beef heifers

Four diets in which peas progressively replaced barley [0% (0P), 30% (30P), 50% (50P), and 100% peas (100P)] and one in which canola meal (CM) replaced 10% of the barley, were fed to 90 beef heifers (initial weight 215.8 ± 13.8 kg). The heifers achieved average daily gains (ADGs) of 0.72, 0.80, 0.79, 0.83, and 0.76 kg d-1 on the five diets, respectively, with the difference between the 0P group and the 100P group being significant (P = 0.028). The total feed costs of gain were $0.786, 0.779, 0.799, 0.860, and 0.817 kg-1 for the five groups, respectively, with the cost of gain being significantly greater (P < 0.05) for the 100P group than for the 0P, 30P or 50P groups. The latter three were not significantly different from each other. Three rumen-cannulated steers (575 ± 56.3 kg) were used to estimate the degradability of the dry matter (DM) and N in the barley straw (BS), CM, barley grain (BG) and peas used in the feeding trial. The rumen undegradable protein (RUP) levels supplied by the five diets were 17.5, 19.0, 19.9, 21.5, and 22.5%, respectively, and all of them met the requirements of these cattle. The RUP content of peas ground through a 1-mm screen was lower than that of peas ground through 2- or 4-mm screens (P < 0.01), which were themselves not significantly different from each other (P = 0.67). The low RUP content of peas was not a limiting factor for growth in backgrounding cattle. Key words: Cattle, field peas, dry matter intake, feed conversion efficiency, rumen me

Cattle herbage utilization patterns under high-density rotational grazing in the Aspen Parkland

Native Aspen Parkland landscapes consist of a complex mosaic of plant communities, including riparian meadows, upland grasslands, and forests. Sustainable livestock production in this environment depends on an understanding of livestock grazing behavior among communities, particularly under contemporary, intensive management rotational grazing systems. This study examined seasonal patterns of absolute (kg ha-1) and relative (%) herbage utilization, as well as plant community visitation, across a Parkland landscape by 150 heifers in two rotations of a high-intensity, low-frequency grazing system. Graminoids constituted more than 92% of the total herbage utilized. Absolute graminoid utilization within each grazing period was greater (P < 0.05) throughout the growing season from riparian meadows (2003 to 2114 kg ha-1) than from upland grasslands (762 to 1041 kg ha-1) or forests (782 to 800 kg ha-1). In contrast, relative graminoid utilization remained similar (P > 0.05) among communities in either rotation, suggesting heifers grazed in proportion to graminoid availability (57–61% in first rotation, 44–54% in second rotation). Although riparian meadows represented a small fraction of the landscape (~ 4%), and provided up to 9.5% of the total forage used, the majority of herbage removal at the paddock level continued to originate from upland grasslands and forests. Patterns of visitation indicated heifers initially visited riparian meadows more often within each 3–4 day grazing period, regardless of entry date. While upland grasslands were least visited in June, forests were least visited in August. Based on these utilization and visitation patterns, we discuss the implications of using high-density, rotational livestock grazing for the sustainable management of Aspen Parkland rangelands. Key words: Aspen forest, cattle grazing, forage quality, herbage utilization, riparian meadow, rotational grazing, upland grassland

Residual feed intake and body composition in young growing cattle

Crossbred steers (n = 176), 7–8 mo of age and from the five BeefBooster strains (M1, M2, M3, M4 and TX), were used to determine the relationships between residual feed intake (RFI) and growth rate, body composition and heat production (HP), and to quantify differences in RFI independent of differences in body composition. Animals with different RFI levels were also characterized for growth, carcass and body compositional traits. Steers from each genetic strain were selected at random and serially slaughtered on 5 pre-selected days of the finishing period. Steers grew at 1.52 (SD = 0.22) kg d-1 and had dry matter intake (DMI) of 8.5 (SD = 1.0) kg d-1 during the last 71 to 183 d before slaughter. Metabolic mid-point weight, average daily gain (ADG), gain in empty body fat and gain in empty body water accounted for 67.9, 8.6, 3.9 and 1.1%, respectively, of the variation in actual feed intake. Similarly, metabolic mid-point weight (68.5%), ADG (8.2%), gain in ultrasound backfat thickness (1.8%), gain in ultrasound marbling score (1.1%) and year (1.3%) accounted for 80.9% of the variation in actual feed intake. Residual feed intake adjusted for differences in estimated composition of gain (estimated gain in empty body fat and water; RFIII) ranged from -2.06 kg d-1 to +1.61 kg d-1 (SD = 0.60 kg d-1). Residual feed intake adjusted for live animal measures of body composition (gain in ultrasound backfat thickness and marbling score; RFIIII) ranged from -2.11 kg d-1 to +1.88 kg d-1 (SD = 0.62 kg d-1). Low RFIIII animals (efficient) had 6.0% lower metabolizable energy intake (MEI), retained 9.3% less energy and had 4.5% lower HP than medium RFIIII animals (P < 0.01). Low RFIIII animals also had 10.2% lower MEI, retained 12.0% less energy and produced 9.3% less heat than high RFIIII animals (P < 0.01). Liver (P <0.01), small and large intestine (P = 0.09) and stomach and intestine (P < 0.01) weights were less in low and medium RFIIII steers compared to high RFIIII steers. There was a trend for low RFIIII steers to have less dissectible carcass fat (P = 0.08), intermuscular fat (P = 0.06), body cavity fat in the butt and loin (P = 0.01), faster accretion rate of empty body water (P = 0.04) and a slower accretion rate of empty body fat (P < 0.01) than medium and high RFIIII steers. A portion of the greater MEI by high RFIIII steer was accounted for by differences in the chemical composition of gain. However, a greater proportion was due to a disproportionate increase in the energy required for maintenance and heat increment of feeding in high RFIIII steers. An attempt should be made to adjust RFI for changes in the chemical composition of gain, possibly by the inclusion of ultrasound backfat thickness and marbling score into the equation for determining RFI. Key words: Cattle, feed efficiency, residual feed intake, remote sensing, GrowSafe System

Meat quality of bison (Bison bison bison) longissimus thoracis et lumborum following very fast chilling

Very fast chilling (VFC; internal muscle temperature of -1°C by 5 h postmortem) was achieved in the longissimus lumborum (LL), but not in the semimembranosus, of lean bison carcasses after only 4 or 6 h of chilling at -35°C. Rigorous chilling caused a shift in moisture loss from carcass cooler shrink to retail drip loss. Sides exposed to VFC conditions had darker LL colour at 24 h postmortem; however, the difference did not persist to 6 d. While chilling for 2 h at -35°C resulted in an increased shear over conventionally chilled samples, the application of VFC for 4 and 6 h decreased mean shear values and resulted in a slight improvement in tenderness consistency. Sensory evaluation panellists noted marginal, non-significant differences. Factors affecting tenderization were the physical prevention of sarcomere shortening due to surface freezing with increased chilling intensity and a contribution from proteolytic enzyme systems over time postmortem. Very fast chilling is an effective means of reducing carcass chilling time while improving tenderness in the LL of lean bison carcasses. Key words: Bison, meat quality, very fast chilling

Fibre type characteristics and postmortem glycolysis of bison (Bison bison bison) Longissimus lumborum

To augment the limited information base, muscle fibre and postmortem glycolytic data from bison longissimus lumborum were compiled. As expected, postmortem glycogen concentration and pH declined while lactate concentration increased. Bison muscle fibres had a greater area, with a greater percentage of fast oxidative glycolytic fibres, and a lesser percentage of fast glycolytic fibres as compared to literature values for beef. Key words: Bison, muscle fibre type, glycogen, lactate

Grazing and the addition of white clover improves the nutritional quality of orchardgrass cultivars

Two experiments were conducted to determine the nutritional quality of orchardgrass (OG) cultivars under hay and rotational grazing systems during the first 2 production years. Crude protein content was higher and fibre content lower in OG managed as rotationally grazed pasture compared with that harvested as hay. The K:Ca + Mg ratio was reduced and Cu deficiency was ameliorated when OG swards contained white clover. Orchardgrass genotypic × sward management effects were also observed. Key words: Orchardgrass, management, potassium, genotypes, quality, pasture, hay

Addition of white clover to orchardgrass pasture improves the performance of grazing lambs, but not herbage production

Two early-maturing cultivars (Juno and Hallmark), three late-maturing orchardgrass cultivars (Sumas, Rideau, and Kay), and a mixture of orchardgrass (Kay) and white clover (Huia) were seeded in a trial with two replicates. Plots were rotationally grazed for 3 successive years after the establishment year by crossbred lambs. Two contrasts were studied: Kay was compared with Kay/Huia and the early-maturing cultivars were compared with the late-maturing cultivars. Dry matter yield was less for the Kay/Huia than Kay in the 3-yr study, crude protein concentration was similar, and nitrate N concentration was less. Concentrations of ADF and NDF were less for Kay/Huia and stocking density was only 78% of that for Kay over the 3 yr. Efficiency of DM utilization for gain averaged 9.6 for Kay/Huia and 11.4 for Kay, but the difference is not significant. Body weight gain for lam bs grazing Kay/Huia was 40% greater than for lambs grazing Kay; gains per hectare were numerically higher, resulting in bigger lambs with more fat cover. There were no differences in DM yield or chemical composition for early- and late-maturing cultivars. Daily gain for lambs grazing early-maturing cultivars tended to be greater, with most of the effect attributed to a response in 1989. Dressed weight, backfat depth relative to dressed weight were all numerically higher for lambs grazing the early-maturing varieties. We conclude that orchardgrass should be seeded with white clover to increase individual animal performance and output of lamb per hectare. Late-maturing cultivars, when planted in monoculture, had no influence on sward productivity, but appeared to offer some advantage for lamb performance. Key words: Grazing, lamb growth, orchardgrass, white clover

Identification of a novel, human multilymphoid progenitor in cord blood

The earliest stages of lymphoid commitment from human pluripotent hematopoietic stem cells have not been defined. A clonogenic subpopulation of CD34(+)CD38(-) cord blood cells were identified that expressed high levels of the CD7 antigen and possessed only lymphoid potential. CD34(+)CD38(-)CD7(+) (CD7(+)) cells uniformly coexpressed CD45RA and HLA-DR; c-kit and Thy-1 expression was absent to low. Clonal analysis demonstrated that single CD7(+) cells could generate B cells, natural killer cells, and dendritic cells but were devoid of myeloid or erythroid potential. In contrast, control CD34(+)CD38(-)CD7(-) (CD7(-)) cells generated both lymphoid and myelo-erythroid cells. The lymphoid potential (generation of lymphoid progeny in bulk and single cell cultures) of CD7(+) cells was equivalent to that of the pluripotent CD7(-) cells. RNA expression studies showed that CD7(+) cells expressed PU.1 and GATA-3, but did not express Pax-5, terminal deoxynucleotide transferase, or CD3epsilon. In contrast to the previously described murine common lymphoid progenitor, the alpha chain of the receptor for interleukin-7 was not detected by fluorescence-activated cell sorting analysis or RNA polymerase chain reaction in CD7(+) cells. These studies identify a clonogenic lymphoid progenitor with both B-cell and natural killer cell lineage potential with a molecular profile that suggests a developmental stage more primitive than previously identified lymphoid progenitors. The CD7(+) phenotype distinguishes primitive human lymphoid progenitors from pluripotent stem cells, thus allowing the study of regulation of early human lymphopoiesis and providing an alternative to pluripotent stem cells for genetic manipulation and transplantation. (Blood. 2001;97:3683-3690)

Epidemiological evidence for a relationship between life events, coping style, and personality factors in the development of breast cancer

OBJECTIVE

Review empirical evidence for a relationship between psychosocial factors and breast cancer development.

METHODS

Standardised quality assessment criteria were utilised to assess the evidence of psychosocial predictors of breast cancer development in the following domains: (a) stressful life events, (b) coping style, (c) social support, and (d) emotional and personality factors.

RESULTS

Few well-designed studies report any association between life events and breast cancer, the exception being two small studies using the Life Events and Difficulties Schedule (LEDS) reporting an association between severely threatening events and breast cancer risk. Seven studies show anger repression or alexithymia are predictors, the strongest evidence suggesting younger women are at increased risk. There is no evidence that social support, chronic anxiety, or depression affects breast cancer development. With the exception of rationality/anti-emotionality, personality factors do not predict breast cancer risk.

CONCLUSION

The evidence for a relationship between psychosocial factors and breast cancer is weak. The strongest predictors are emotional repression and severe life events. Future research would benefit from theoretical grounding and greater methodological rigour. Recommendations are given.

Proteolysis of cubitus interruptus in Drosophila requires phosphorylation by protein kinase A

The Hedgehog signal transduction pathway is involved in diverse patterning events in many organisms. In Drosophila, Hedgehog signaling regulates transcription of target genes by modifying the activity of the DNA-binding protein Cubitus interruptus (Ci). Hedgehog signaling inhibits proteolytic cleavage of full-length Ci (Ci-155) to Ci-75, a form that represses some target genes, and also converts the full-length form to a potent transcriptional activator. Reduction of protein kinase A (PKA) activity also leads to accumulation of full-length Ci and to ectopic expression of Hedgehog target genes, prompting the hypothesis that PKA might normally promote cleavage to Ci-75 by directly phosphorylating Ci-155. Here we show that a mutant form of Ci lacking five potential PKA phosphorylation sites (Ci5m) is not detectably cleaved to Ci-75 in Drosophila embryos. Moreover, changes in PKA activity dramatically altered levels of full-length wild-type Ci in embryos and imaginal discs, but did not significantly alter full-length Ci5m levels. We corroborate these results by showing that Ci5m is more active than wild-type Ci at inducing ectopic transcription of the Hh target gene wingless in embryos and that inhibition of PKA enhances induction of wingless by wild-type Ci but not by Ci5m. We therefore propose that PKA phosphorylation of Ci is required for the proteolysis of Ci-155 to Ci-75 in vivo. We also show that the activity of Ci5m remains Hedgehog responsive if expressed at low levels, providing further evidence that the full-length form of Ci undergoes a Hedgehog-dependent activation step.

A study of growth and carcass traits in dehorned and polled composite bulls

Phenotypically dehorned (genetically horned) and polled bulls were similar for birth, weaning weight, pre- and post-weaning ADG, carcass weight, grade fat, marbling, rib-eye area, cutability and carcass grade. Polled bulls had higher (P < 0.02) fat over the rib-eye compared with dehorned. The similarity in growth and a majority of carcass traits between polled and horned, would suggest that breeding for polledness may be recommended to eliminate horns. Key words: Dehorned, polled, growth, carcass traits, bulls

Predictors of breast cancer in women recalled following screening

BACKGROUND

Established risk factors are associated with between 25 and 56% of breast cancer cases, but the relative importance and relevance to different age groups is unclear.

METHODS

This case-control study examines established risk factors in 298 women with breast cancer and 1926 women without breast cancer aged 40-87 who were recalled for assessment following routine mammography.

RESULTS

The cancer group were significantly older than the non-cancer group (F1,222 = 107.6; P < 0.0001). Postmenopausal obesity increased the odds of developing breast cancer (OR: 2.35; CI: 1.33-4.16). The breast cancer group were more likely to have used oral contraceptives (OR: 1.50; CI: 1.09-2.05), and women who used contraceptives for more than 10 years in total were at the highest risk (OR: 1.73; CI: 1.13-2.65). Daily consumption of alcohol was also associated with increased risk of developing breast cancer (OR: 1.62; CI: 1.13-2.33). Reproductive factors and a family history of breast cancer did not affect the odds of developing breast cancer and the reasons for these findings are explored.

CONCLUSIONS

Results suggest that the effects of weight reduction in reducing postmenopausal breast cancer risk should be assessed.

A comparison of reproductive and growth traits of horned and polled cattle in three synthetic beef lines

The data for the study were obtained over an 11 yr period and the number of observations varied from 2663 to 4263 depending on the trait that was studied. The objective was to compare the reproduction and growth traits of genetically horned and polled cattle in three synthetic lines of beef cattle. No differences (P > 0.05) were observed between horned and polled cattle in all lines for pregnancy, calving and weaning rates, calf birth and weaning weights, calf preweaning average daily gains, dystocia score, cow weights and cow condition scores at calf birth and calf weaning. We advocate the use of polled cattle for breeding, which is a welfare friendly alternative and circumvents the need for dehorning. Key words: Horned, polled cattle, dehorning, reproduction, growath

Stable transduction of quiescent CD34(+)CD38(-) human hematopoietic cells by HIV-1-based lentiviral vectors

We compared the efficiency of transduction by an HIV-1-based lentiviral vector to that by a Moloney murine leukemia virus (MLV) retroviral vector, using stringent in vitro assays of primitive, quiescent human hematopoietic progenitor cells. Each construct contained the enhanced green fluorescent protein (GFP) as a reporter gene. The lentiviral vector, but not the MLV vector, expressed GFP in nondivided CD34(+) cells (45.5% GFP+) and in CD34(+)CD38(-) cells in G0 (12.4% GFP+), 48 hr after transduction. However, GFP could also be detected short-term in CD34(+) cells transduced with a lentiviral vector that contained a mutated integrase gene. The level of stable transduction from integrated vector was determined after extended long-term bone marrow culture. Both MLV vectors and lentiviral vectors efficiently transduced cytokine-stimulated CD34(+) cells. The MLV vector did not transduce more primitive, quiescent CD34(+)CD38(-) cells (n = 8). In contrast, stable transduction of CD34(+)CD38(-) cells by the lentiviral vector was seen for over 15 weeks of extended long-term culture (9.2 +/- 5.2%, n = 7). GFP expression in clones from single CD34(+)CD38(-) cells confirmed efficient, stable lentiviral transduction in 29% of early and late-proliferating cells. In the absence of growth factors during transduction, only the lentiviral vector was able to transduce CD34(+) and CD34(+)CD38(-) cells (13.5 +/- 2.5%, n = 11 and 12.2 +/- 9.7%, n = 4, respectively). The lentiviral vector is clearly superior to the MLV vector for transduction of quiescent, primitive human hematopoietic progenitor cells and may provide therapeutically useful levels of gene transfer into human hematopoietic stem cells.

Comparison of objective external carcass measurements and subjective conformation scores for prediction of lamb carcass quality

Carcass measurements were collected from 1505 lambs over a 2-yr period by a single technician. The lambs (rams, ewes and wethers) were classified as either meat-type or wool-type, with meat-type subdivided by frame size into light, medium or large. Carcass measurements included carcass length (L), length of hind leg (T), depth of hind leg (H) and circumference of hind leg (G). Agriculture and Agri-Food Canada graders measured tissue depth of all lambs at the GR site (11 cm from carcass midline over the 12th rib) and assigned subjective conformation scores for the regions of the leg, loin and shoulder. Sixty-nine lambs across groups were dissected into primal cuts to determine saleable meat yield. Carcass length and T decreased (P < 0.05) with increasing conformation score, whereas G and H increased (P < 0.05) with increasing conformation score. Wool-breed and light-frame lambs had lower conformation scores (P < 0.01) for the regions of the leg and loin than did medium- and large-frame lambs. Comparing the results of carcass dissection, wool-breed lambs had a lower saleable meat yield (P < 0.05) than large-frame lambs. Saleable meat yield also tended to be lower for light-frame than for medium- and large-frame lambs, although the numbers of medium- and light-frame lambs dissected were low. The carcass measurements used in this study accurately predicted percentage of the high priced leg cuts (R2 = 0.80, RSD = 0.6%), and were marginally more accurate than subjective conformation scores in predicting saleable yield from dissection (R2 = 0.61, RSD = 1.3%). However the carcass measurements used in this study were not valuable predictors of percentages of shoulder or loin and rack in the primal cuts. These data do not indicate any unjustified bias in the subjective conformation scores currently in use in the Canadian Classification System for lamb, as the breed types and frame sizes assigned lower conformation scores also had lower saleable meat yields. Key words: Measurement, lamb, carcass, meat yield

The use of a digital imaging system in a dermatologic surgery practice

BACKGROUND

Digital imaging systems are now commercially available, reasonably affordable, and much improved in quality.

OBJECTIVE

To present our 2-year experience with a digital imaging system in Mohs and dermatologic surgery practice and to inform readers of the equipment needed, its cost, uses, advantages, and disadvantages compared with conventional photography.

CONCLUSION

The advantages of a digital imaging system include quality images, easy storage and retrieval, and cost-effectiveness. The disadvantages are few: a substantial initial investment and the training of office personnel in its use and maintenance. Uses include monitoring nevomelanocytic lesions, surgical photo documentation, medical records, and a photographic research database.

The p38 and ERK MAP kinase pathways cooperate to activate Ternary Complex Factors and c-fos transcription in response to UV light

We investigated the activation of c-fos transcription following UV irradiation, a 'stress' stimulus. In both HeLa TK- and NIH 3T3 cells the Serum Response Element is required for efficient UV-induced c-fos transcription, and in HeLa TK- cells the Ternary Complex Factor (TCF) binding site contributes substantially to activation. Consistent with this, UV irradiation activates LexA-TCF fusion proteins more strongly in HeLa TK- than in NIH 3T3 cells. The TCF C-termini of the TCFs are substrates for UV-induced MAP kinases: both the Elk-1 and SAP-1a C-termini are efficiently phosphorylated by the p38 MAPK, but only the Elk-1 C-terminus is a good substrate for the SAPK/JNKs. The specificity and activation kinetics of TCF C-terminal kinases, and the susceptibility of transcriptional activation by LexA-TCF fusion proteins to specific inhibitors of different MAPK pathways, show that both the ERK and p38 MAPK pathways contribute to TCF activation in response to UV irradiation. Activity of both these pathways is also required for the response of the c-fos gene itself to UV stimulation.

Glycogen metabolites and meat quality in feed-restricted re-fed beef heifers

Twenty-four Hereford crossbred heifers weighing 222 kg (22 kg SD) and aged 226 d (13 d SD) on day 0 were used to investigate the effects of feed restriction (period 1) followed by realimentation (period 2) on hepatic and longissimus muscle glycogen metabolites and meat quality. The heifers were randomly assigned in equal numbers to either ad libitum feeding (ADLIB) or maintenance feeding for 92 d followed by realimentation (REST), and serially slaughtered over a wide range of liveweights (200–460 kg). The concentrations of glycogen, its metabolites, and the total glucidic potential (GP) were determined from portions of the caudate lobe of the liver and the longissimus lumborum (LL) muscle. Meat quality assessment of the longissimus thoracis (LT) was done by objective means. Hepatic glycogen concentration was lower (P = 0.05) in REST than in ADLIB heifers, and GP tended to show a similar pattern (P = 0.07). There were no significant differences in the concentrations of glycogen or its metabolites in the LL of REST compared with ADLIB heifers. However, the heifers slaughtered during period 1 had lower muscle glycogen (P = 0.04) and higher lactate (P < 0.01) concentrations than those slaughtered during period 2. REST heifers had lighter slaughter weights resulting in smaller ribeye areas (P = 0.03), lower intramuscular fat concentration (P < 0.01) and higher moisture content (P < 0.01). Independent of slaughter weight, REST heifers had higher drip loss (P = 0.05) and lower L * (P = 0.01) than ADLIB heifers. These results suggest that feed restriction affects hepatic glycogen reserves and also has minor effects on meat quality traits in beef heifers. However, there was no indication that meat from REST heifers had severe quality defects such as DFD (dark, firm, dry) meat. Key words: Feed restriction, realimentation, longissimus muscle, liver, glucidic potential, meat quality

The effects of catch-up (compensatory) growth on reproductive performance of beef heifers

Fifty-four heifer calves were allocated to five feeding/weaning treatments at birth in April/May 1990: 1) VEW (n = 11) dams feed-restricted for 3 mo before and 2 mo after calving; calves weaned in June onto gram-supplemented pasture and then into a drylot in October; 2) EW1 (n = 10) dams not restricted; calves weaned in August (unsupplemented pasture) into drylot in October; 3) EW2 (n = 10) dams not feed-restricted; calves weaned directly into drylot in August; 4) LW1 (n = 12) dams feed restricted for 3 mo before, but not after calving; calves weaned directly into drylot in October, 5) LW2 (n = 11): dams not restricted; calves weaned directly into drylot in October. The very early (VEW) and early (EW1, EW2) weaned heifers grew significantly slower than the later-weaned ones (LW1, LW2) from birth to September, and were still significantly lighter at 12–13 mo of age (May 1991). Recovery of liveweight-for-age was achieved by EW2 heifers by 18 mo and VEW and EW1 by about 23 mo of age. Early weaning treatments delayed age but not weight at first estrus (P < 0.05) yet the number of heifers conceiving and calving, and all associated reproductive data, including rebreeding success were unaffected by treatment (P > 0.05). Despite a delay in first estrus, reproductive efficiency and calving performance were not impaired by early feed restriction in heifers conceiving at 15 mo of age. Key words: Beef heifers, feed restriction, fertility, reproduction, catch-up growth

The effects of pre- and early post-calving management on reproductive performance of beef cows

One hundred and thirty-four pregnant beef cows (liveweight = 544.3 kg ± 73 3 kg SD; condition score = 3.5 ± 0.3 SD), were randomly assigned in January to five management treatments (combinations of feed restriction and weaning time) to study the effects on calving and rebreeding performance. Twenty-seven were feed-restricted (54.7 MJ DE d−1) for the last 3 mo of pregnancy then realimented (3REST); their calves were weaned in October. Thirty were feed-restricted for the last 3 mo of pregnancy (54.7 MJ DE d−1) and the first 2 mo of lactation (99.6 MJ DE d−1), then their calves were weaned and turned out to graze in June (5REST). The remaining 77 cows (UNREST) were supplemented on range with 153.5 MJ DE d−1 from January until calving. Their calves were weaned in either August (one group of 26 calves directly into a feedlot, a second group of 26 onto unsupplemented range) or October (25 calves directly into a feedlot). All cows grazed together on the range from June onwards. After calving, the restricted (3REST and 5REST) cows were significantly lighter (464.4 and 469.5 kg vs. 506.9 kg) and thinner (condition scores 2.5 and 2.6 vs. 3.0) than the UNREST cows, but the percentage of cows calving calf mortality, assisted births calving dates, udder scores and mean birth weight of calves were not affected (P > 0.05) by pre-calving nutrition. Catch-up growth was evident in both the 3REST and 5REST cows once exposed to higher energy feeding. There were no significant effects (P > 0.05) of the management (nutrition and weaning) treatments on the following year s breeding and calving performance. It is concluded that the combinations of nutrition and weaning used in this study did not necessarily impair calving or rebreeding performance of beef cows, which calved in condition score 2.5 or above. Key words: Beef cows, feed restriction, reproduction, condition score, rebreeding, birthweight

Integration of growth factor signals at the c-fos serum response element

A transcription factor ternary complex composed of serum response factor (SRF) and a second factor, ternary complex factor (TCF), mediates the response of the c-fos Serum Response Element to growth factors and mitogens. In NIH3T3 fibroblasts, TCF binding is required for transcriptional activation by the SRE in response to activation of the Ras-Raf-ERK pathway. We compared the properties of three members of the TCF family, Elk-1, SAP-1 and SAP-2 (ERP/NET). Although all the proteins contain sequences required for ternary complex formation with SRF, only Elk-1 and SAP-1 appear to interact with the c-fos SRE efficiently in vivo. Each TCF contains a C-terminal activation domain capable of transcriptional activation in response to activation of the Ras-Raf-ERK pathway, and this is dependent on the integrity of S/T-P motifs conserved between all the TCF family members. In contrast, activation of the SRE by whole serum and the mitogenic phospholipid LPA requires SRF binding alone. Constitutively activated members of the Rho subfamily of Ras-like GTPases are also capable of inducing activation of the SRE in the absence of TCF; unlike activated Ras itself, these proteins do not activate the TCFs in NIH3T3 cells. At the SRE, SRF- and TCF-linked signalling pathways act synergistically to potentiate transcription.

The prediction of saleable meat yield in lamb carcasses

A total of 281 lamb carcasses covering three weight groups (18–22.9, 23–25.9 and 26–30 kg) and fatness (< 3 mm, 3–5 mm and > 5 mm) were used to determine the usefulness of several carcass measurements for predicting saleable meat yield. Carcasses were measured for fat and muscle depth, 3–4 cm from the mid-line between the 10th and 11th ribs, 12th and 13th ribs and immediately adjacent to the 13th rib using a Hennessey Grading Probe. This technique also determined total tissue depth at 11 cm from the mid-line between the 10th and 11th and 12th and 13th ribs. The depth of tissues over the 12th rib 11 cm from the mid-line was measured with a ruler. Carcasses were also visually assessed for muscle development (conformation score) on a 5-point scale (1 = thinly fleshed; 5 = thickly fleshed). All carcasses were fabricated into primal cuts which were trimmed to 5 mm of fat and deboned to provide an estimate of saleable meat yield. Ewe lamb carcasses had a higher proportion of kidney fat than wethers in all weight and fat groups (which ranged from 2.6 to 17.9 g kg−1 carcass weight). Saleable meat yield decreased as carcasses became fatter, whereas weight group had little influence on saleable meat yield within a fat group. Ewe lamb carcasses had lower saleable meat yields than wether lamb carcasses, mainly because of their higher amounts of kidney fat. A ruler measurement of tissue depth over the 12th rib combined with carcass conformation score provided the most precise prediction (R2 = 0 61; RSD 17.1) of saleable meat yield. It was concluded that a simple manual system based on these two measurements provided an adequate prediction of saleable meat yield. The accuracy of the procedure would be increased by excluding kidney fat from carcass weight for the prediction of saleable meat yield. Key words: Lamb, carcass, composition, probe, fat, grade

Hormonal status, metabolic changes, and resting metabolic rate in beef heifers undergoing compensatory growth

Twelve recently weaned Hereford crossbred heifers weighing 227 kg (12 kg SD) and aged 230 d (8 d SD) on d 0 were used to investigate physiological responses associated with compensatory growth. Six heifers were allotted to ad libitum intake (ADLIB) and six were restricted to a maintenance diet for 95 d followed by realimentation (REST). Plasma collected from all heifers during feed restriction (d 0, 20, 48) and realimentation (d 104, 125, 153, 195) was analyzed for growth hormone (GH), insulin-like growth factor I (IGF-I), thyroid hormones (thyroxine [T4] and triiodothyronine [T3]), insulin, glucose, nonesterified fatty acids (NEFA), blood urea nitrogen (BUN), and 3-methyl histidine (3-MH). Resting metabolic rate (RMR) was measured 5 d before and 15 and 36 d after the beginning of realimentation. Feed restriction was associated with higher (P < .05) plasma concentrations of GH and NEFA and lower (P < .05) concentrations of IGF-I, T4, T3, insulin, and glucose. The BUN concentration was lower (P = .05) in REST than in ADLIB heifers on d 48, whereas 3-MH was not affected during the first 48 d of feed restriction. The RMR was lower (P < .05) in REST than in ADLIB heifers during feed restriction. During realimentation, the ADG of REST heifers was higher (P = .001) than that of ADLIB heifers. Concentrations of IGF-I, insulin, glucose, and NEFA in REST heifers increased and no differences (P > .05) between treatments were observed on d 104 (d 10 of realimentation) and thereafter. Conversely, GH concentration in REST heifers remained elevated through d 104 but dropped to ADLIB levels by d 125 (d 31 of realimentation). The T4 and T3 concentrations remained lower (P < .05) in REST than in ADLIB heifers after 10 d of realimentation but rose to control levels by d 31 of realimentation. The RMR was lower (P < .05) in REST than in ADLIB heifers 15 d into realimentation; however, no difference was found between treatments by d 36 of realimentation. These results indicate that enhanced growth rates in the early phase of compensatory growth are associated with the physiological response of the GH-IGF-I-insulin axis coupled with reduced maintenance requirement due to slower metabolic rate in restricted-refed heifers.