Dietary starch promotes hepatic lipogenesis in barramundi (Lates calcarifer).

Barramundi (Lates calcarifer) are a highly valued aquaculture species, and, as obligate carnivores, they have a demonstrated preference for dietary protein over lipid or starch to fuel energetic growth demands. In order to investigate how carnivorous fish regulate nutritional cues, we examined the metabolic effects of feeding two isoenergetic diets that contained different proportions of digestible protein or starch energy. Fish fed a high proportion of dietary starch energy had a higher proportion of liver SFA, but showed no change in plasma glucose levels, and few changes in the expression of genes regulating key hepatic metabolic pathways. Decreased activation of the mammalian target of rapamycin growth signalling cascade was consistent with decreased growth performance values. The fractional synthetic rate (lipogenesis), measured by TAG 2H-enrichment using 2H NMR, was significantly higher in barramundi fed with the starch diet compared with the protein diet (0·6 (se 0·1) v. 0·4 (se 0·1) % per d, respectively). Hepatic TAG-bound glycerol synthetic rates were much higher than other closely related fish such as sea bass, but were not significantly different (starch, 2·8 (se 0·3) v. protein, 3·4 (se 0·3) % per d), highlighting the role of glycerol as a metabolic intermediary and high TAG-FA cycling in barramundi. Overall, dietary starch significantly increased hepatic TAG through increased lipogenesis. Compared with other fish, barramundi possess a unique mechanism to metabolise dietary carbohydrates and this knowledge may define ways to improve performance of advanced formulated feeds.

Dynamic damage in carbon-fibre composites.

The Taylor test is used to determine damage evolution in carbon-fibre composites across a range of strain rates. The hierarchy of damage across the scales is key in determining the suite of operating mechanisms and high-speed diagnostics are used to determine states during dynamic loading. Experiments record the test response as a function of the orientation of the cylinder cut from the engineered multi-ply composite with high-speed photography and post-mortem target examination. The ensuing damage occurs during the shock compression phase but three other tensile loading modes operate during the test and these are explored. Experiment has shown that ply orientations respond to two components of release; longitudinal and radial as well as the hoop stresses generated in inelastic flow at the impact surface. The test is a discriminant not only of damage thresholds but of local failure modes and their kinetics. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

Evidence that leptin genotype is associated with fertility, growth, and milk production in Holstein cows.

This study investigated associations between single nucleotide polymorphisms (SNP) in the leptin, leptin receptor, and neuropeptide Y (NPY) genes with growth, milk production, and fertility traits. Holstein Friesian heifers from 19 UK dairy farms were recruited at birth, providing an initial population of 509. Animals were monitored until they either reached the end of their second lactation or were culled. Size (weight, height, length, girth) was measured at 1, 6, and 15 mo to assess growth traits. Heifer fertility was assessed by recording age at service, age at conception, age at first calving, and number of services. Cow fertility was assessed by recording days from calving to service and conception, services per conception, percentage of animals in calf at 100 d after calving and the calving interval in each lactation. Milk production was recorded as days in milk, total milk per lactation, 305-d yield, milk per day, and peak yield. Mixed model analyses revealed that leptin SNP were associated with early skeletal growth (height, A1457G; length, A59V), fertility (UASMS1, UASMS2, A1457G, A59V) and milk production (A59V). The leptin receptor SNP (T945M) was only weakly associated with milk per day and days to first service. The NPY SNP (NPY1) was associated with the prevalence of the animal being in calf 100 d after calving and 305-d milk yield in the first lactation. The association of leptin SNP with fertility traits in heifers, in addition to lactating cows, suggests that some effects on fertility are direct and not necessarily mediated via altered tissue mobilization. In accord with this, other work has shown that leptin can affect oocyte quality and early embryo development. These results support the use of leptin SNP to inform marker-assisted selection in dairy cows.

Expression of the herpes simplex virus type 2 latency-associated transcript enhances spontaneous reactivation of genital herpes in latently infected guinea pigs.

The latency-associated transcript (LAT) is the only herpes simplex virus (HSV) gene product detectable in latently infected humans and animals. In this report, we show that a 624-bp deletion in the promoter of the HSV-2 LAT had no discernable effect on viral growth in tissue culture or in acute genital infection of guinea pigs, but impaired LAT accumulation and led to a marked decrease in spontaneous genital recurrences when compared with the behavior of wild-type and rescuant strains. Differences in the ability of the mutant to replicate, or in how readily it established or maintained latency did not account for this finding. Thus, HSV LAT expression facilitates the spontaneous reactivation of latent virus.

The characteristic site-specific reactivation phenotypes of HSV-1 and HSV-2 depend upon the latency-associated transcript region.

After replication at sites of initial inoculation, herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) establish lifelong latent infections of the sensory and autonomic neurons of the ganglia serving those sites. Periodically, the virus reactivates from these neurons, and travels centripetally along the neuronal axon to cause recurrent epithelial infection. The major clinically observed difference between infections with herpes simplex virus type 1 and type 2 is the anatomic site specificity of recurrence. HSV-1 reactivates most efficiently and frequently from trigeminal ganglia, causing recurrent ocular and oral-facial lesions, while HSV-2 reactivates primarily from sacral ganglia causing recurrent genital lesions. An intertypic recombinant virus was constructed and evaluated in animal models of recurrent ocular and genital herpes. Substitution of a 2.8-kbp region from the HSV-1 latency-associated transcript (LAT) for native HSV-2 sequences caused HSV-2 to reactivate with an HSV-1 phenotype in both animal models. The HSV-2 phenotype was restored by replacing the mutated sequences with wild-type HSV-2 LAT-region sequences. These sequences or their products must act specifically in the cellular environments of trigeminal and sacral neurons to promote the reactivation patterns characteristic of each virus.

Impact failure in two silicates revealed by ultrafast, in situ, synchrotron X-ray microscopy.

To travel safely behind screens that can protect us from stones and hail, we must understand the response of glass to impact. However, without a means to observe the mechanisms that fail different silicate architectures, engineering has relied on external sensors, post-impact examination and best-guess to glaze our vehicles. We have used single and multi-bunch, X-ray imaging to differentiate distinct phases of failure in two silicates. We identified distinct micromechanisms, operating in tandem and leading to failure in borosilicate glass and Z-cut quartz. A surface zone in the amorphous glass densifies before bulk fracture occurs and then fails the block, whilst in quartz, fast cracks, driven down cleavage planes, fails the bulk. Varying the rate at which ejecta escapes by using different indenter tip geometries controls the failed target's bulk strength. This opens the way to more physically based constitutive descriptions for the glasses allowing design of safer, composite panels by controlling the impulses felt by protective screens.

Metabolic traits affecting growth rates of pre-pubertal calves and their relationship with subsequent survival.

This study related growth and metabolic traits in Holstein-Friesian calves (n=45) to subsequent performance and longevity. Animals were measured at birth, 3, 6 and 9 months (weight, crown rump length (CRL), heart girth and height). Endocrine and metabolic traits were assessed at 6 months of age. These traits were not influenced by sire (n=5). Milk production and mortality records were obtained through 3 lactations. Seven heifers failed to achieve a lactation, 6 were culled after one, 17 after two and 15 (33%) survived >/=3 lactations. Birth weight and girth but not skeletal measures were highly positively correlated with the repeated size measurements at 3-9 months. Calves with higher cortisol at 6 months were smaller in weight and girth at 3 months, with reduced 3-6 months skeletal growth. GH secretion was related to height, weight and growth, whereas urea was most strongly related to CRL. Calves not achieving a single lactation had lower IGF-I. Calves with higher glucose or BHB were more likely to be culled after 2 lactations, an effect which was independent of yield. Size and metabolic measurements of growing calves may therefore prove useful in predicting longevity.

The effect of parenteral supplementation of vitamin E with selenium on the health and productivity of dairy cattle in the UK.

Recent work has suggested that the recommended intakes of vitamin E for dairy cattle need to be increased, particularly in dry cows. However, these suggestions are based on data from cattle in the USA, which may have significantly different oxidative stresses than European cattle. This study, which involved 594 cattle on three dairy farms, was designed to determine the effect of increased vitamin E supplementation on the health and fertility of UK dairy cows. Cattle were randomly allocated to receive either two intramuscular injections of 2100 mg of vitamin E (and 7 g of sodium selenite) 2 weeks before calving and on the day of calving, or no additional vitamin E supplementation. Although supplementation had no effect on milk yield, reproductive efficiency, or incidence of uterine infections, supplemented cattle had a lower risk of culling and a lower rate of mastitis. These figures were economically significant but not statistically significant at the 10% level. Supplementation reduced the incidence of retained fetal membranes from 6.5% to 3%, an effect which was almost significant at the 5% level. If these data are representative they suggest that vitamin E recommendations for UK cattle should be reassessed.

Differences between primiparous and multiparous dairy cows in the inter-relationships between metabolic traits, milk yield and body condition score in the periparturient period.

During the early postpartum period dairy cows mobilize fat and muscle to support lactation. This is associated with alterations in blood metabolite and hormone profiles which in turn influence milk yield and fertility. This study developed models to determine how metabolic traits, milk yield and body condition score were inter-related at different times in the periparturient period and to compare these relationships in primiparous (PP, n=188) and multiparous (MP, n=312) cows. Data from four previous studies which included information on blood metabolic parameters, parity, milk yield, body condition score and diet were collated into a single dataset. Coefficients of polynomial equations were calculated for each trait between -1 week pre-calving and week +7 postpartum using residual maximum likelihood modelling. The completed dataset was used in a multiple correlation model to determine how the best fit curves were related to each other over time. PP cows had higher concentrations of insulin-like growth factor-I and lower beta-hydroxybutyrate concentrations throughout, higher leptin concentrations pre-partum and both the peak in non-esterified fatty acids and the nadir in urea concentration occurred earlier after calving. These differences were associated with significantly lower milk production. Leptin concentrations fell at calving and were related to body condition score. Insulin was negatively correlated with yield in MP cows only. In MP cows the relationship between insulin-like growth factor-I and yield switched from negative to positive between weeks +4 and +7. Both beta-hydroxybutyrate and urea were positively related to yield in PP cows. In contrast, in MP cows beta-hydroxybutyrate was negatively correlated with yield and urea was strongly related to body condition score but not yield. These results suggest that there are differences in the control of tissue mobilization between PP and MP cows which may promote nutrient partitioning into growth as well as milk during the first lactation.

Multiple correlation analyses of metabolic and endocrine profiles with fertility in primiparous and multiparous cows.

Results from 4 studies were combined (representing a total of 500 lactations) to investigate the relationships between metabolic parameters and fertility in dairy cows. Information was collected on blood metabolic traits and body condition score at 1 to 2 wk prepartum and at 2, 4, and 7 wk postpartum. Fertility traits were days to commencement of luteal activity, days to first service, days to conception, and failure to conceive. Primiparous and multiparous cows were considered separately. Initial linear regression analyses were used to determine relationships among fertility, metabolic, and endocrine traits at each time point. All metabolic and endocrine traits significantly related to fertility were included in stepwise multiple regression analyses alone (model 1), including peak milk yield and interval to commencement of luteal activity (model 2), and with the further addition of dietary group (model 3). In multiparous cows, extended calving to conception intervals were associated prepartum with greater concentrations of leptin and lesser concentrations of nonesterified fatty acids and urea, and postpartum with reduced insulin-like growth factor-I at 2 wk, greater urea at 7 wk, and greater peak milk yield. In primiparous cows, extended calving to conception intervals were associated with more body condition and more urea prepartum, elevated urea postpartum, and more body condition loss by 7 wk. In conclusion, some metabolic measurements were associated with poorer fertility outcomes. Relationships between fertility and metabolic and endocrine traits varied both according to the lactation number of the cow and with the time relative to calving.

A meta-analysis of the effects of Vitamin E supplementation on the incidence of retained foetal membranes in dairy cows.

A meta-analysis was performed to consolidate the results of studies which have evaluated the effects of Vitamin E supplementation during the dry period on the risk of retained foetal membranes (RFM) in the dairy cow. Twenty studies demonstrated a beneficial response to Vitamin E whilst 21 found no benefit and 3 reported an increase in the incidence of RFM in treated cows. The odds ratios (OR) of the available studies exhibited significant heterogeneity, so multivariable logistic regression analysis was performed to enable the identification of factors associated with the response to Vitamin E supplementation. Our multivariable analysis included parity and Vitamin E supplementation (control/treated) in the model, because all other factors were co-linear. Results indicated that Vitamin E supplementation led to a reduction in the incidence of RFM. A second multivariable analysis was undertaken on a subset of the data including only supplemented cows to determine the influence of supplementation factors on the risk of RFM. All factors were co-linear with each other, therefore, only type of Vitamin E supplementation was included in this analysis. The regression model demonstrated that administration of the synthetic Vitamin E alpha-tocopheryl acetate was associated with a lower risk of RFM than treatment with natural Vitamin E (alpha-tocopherol) (P=0.047, OR=0.49), whereas the difference between the synthetic Vitamin E alpha-tocopherol acetate and natural Vitamin E just failed to attain statistical significance (P=0.059, OR=0.53). Overall the analyses indicate that Vitamin E supplementation during the dry period is associated with a reduced risk of RFM, and that the synthetic forms of Vitamin E are more effective than the natural compound.

Influence of negative energy balance on cyclicity and fertility in the high producing dairy cow.

The peripartum period is of critical importance to subsequent health and fertility. Most cows enter a state of negative energy balance (NEB) associated with many metabolic changes which have carry over effects on the resumption and normality of estrous cyclicity and the success of subsequent inseminations. A dataset on 500 lactations explored the relationships between metabolic traits measured before and after calving with fertility. Stepwise multiple regression analysis showed that longer calving to conception intervals were associated with altered profiles of IGF-I, urea and body condition score. These relationships between metabolic profiles and fertility differed between first lactation cows (which are still growing but produce less milk) and mature animals. Early postpartum the liver undergoes extensive biochemical and morphological modifications to adapt to NEB, the uterus is extensively remodeled and must clear bacterial infections, and the ovary must resume ovulatory cycles. RNA isolated from liver and uterine tissues harvested 2 weeks postpartum from cows in mild (MNEB) and severe (SNEB) energy balance was used to screen the Affymetrix 23K bovine microarray. In liver, SNEB resulted in differential expression of key genes involved in lipid catabolism, gluconeogenesis, and the synthesis and stability of IGF-I. This was accompanied by reduced systemic concentrations of IGF-I which is likely to impact on ovarian function and early embryo development. Within endometrium, cows in SNEB showed histological evidence for higher levels of inflammation and the microarray analysis identified groups of differentially expressed genes involved in tissue remodeling and immune response. This may delay uterine repair after calving, likely contributing to the observed reduction in fertility.

On compression and damage evolution in two thermoplastics.

The well-known Taylor cylinder impact test, which follows the impact of a flat-ended cylindrical rod onto a rigid stationary anvil, is conducted over a range of impact speeds for two polymers, polytetrafluoroethylene (PTFE) and polyetheretherketone (PEEK). In previous work, experiments and a model were developed to capture the deformation behaviour of the cylinder after impact. These works showed a region in which spatial and temporal variation of both longitudinal and radial deformation provided evidence of changes in phase within the material. In this further series of experiments, this region is imaged in a range of impacted targets at the Diamond synchrotron. Further techniques were fielded to resolve compressed regions within the recovered polymer cylinders that showed a fracture zone in the impact region. The combination of macroscopic high-speed photography and three-dimensional X-ray imaging has identified the development of failure with these polymers and shown that there is no abrupt transition in behaviours but rather a continuous range of responses to competing operating mechanisms. The behaviours noted in PEEK in these polymers show critical gaps in understanding of polymer high strain-rate response.

Immunogenicity evaluation of DNA vaccines that target guinea pig cytomegalovirus proteins glycoprotein B and UL83.

Vaccines are needed for control of congenital human cytomegalovirus (HCMV) infection. Although the species-specificity of cytomegaloviruses precludes preclinical evaluation of HCMV vaccines in animal models, the guinea pig cytomegalovirus (GPCMV), which causes disease in utero, is a relevant model for the study of vaccines against congenital infection. We investigated whether DNA vaccines that target two GPCMV proteins, glycoprotein B (gB) and UL83 (pp65), are capable of eliciting immune responses in vivo. After cloning each gene into an expression vector, DNA was delivered by intramuscular inoculation and by pneumatic epidermal delivery. In Swiss-Webster mice, anti-gB titers were significantly higher after epidermal delivery. After epidermal inoculation in guinea pigs, all gB-immunized animals (n = 6) had antibody responses comparable to those induced by natural infection. Viral neutralization titers ranged from 1:64 to greater than 1:128. A GPCMV UL83 DNA vaccine also elicited an antibody response in all immunized guinea pigs (n = 6) after epidermal administration. Immunoprecipitation and Western blot assays confirmed that immune sera were immunoreactive with virion-associated UL83 and gB proteins. We conclude that DNA vaccines against GPCMV structural proteins are immunogenic, and warrant further investigation in the guinea pig model of congenital CMV infection.

Cyclic HPMPC is safe and effective against systemic guinea pig cytomegalovirus infection in immune compromised animals.

Cidofovir (HPMPC) is licensed for the treatment of cytomegalovirus (CMV) retinitis in patients with AIDS but its use is limited by nephrotoxicity. We evaluated the safety and efficacy of 1-[((s)-2-hydroxy-2-oxo-1,4,2-dioxaphosphorinan-5-yl)methyl]cytosi ne dihydrate (CHPMPC) the cyclic congener of cidofovir. Treatment was well tolerated both in normal guinea pigs and in animals immune compromised with cyclophosphamide. Further, blood chemistry analysis showed no adverse effects of CHPMPC treatment on kidney or liver function. In efficacy studies in immune compromised guinea pigs challenged with a virulent salivary gland passaged guinea pig CMV, CHPMPC treatment significantly reduced mortality resulting from disseminated virus infection. Quantitative culture showed that treatment also significantly reduced virus replication in the liver and spleen, but not the lungs of infected animals. The efficacy of CHPMPC combined with its improved safety profile appear to make it an attractive alternative to cidofovir for the treatment of herpesvirus infections. Further evaluation is warranted.

Pathogenesis of acyclovir-resistant herpes simplex type 2 isolates in animal models of genital herpes: models for antiviral evaluations.

Our understanding of the pathogenesis of acyclovir (ACV)-resistant herpes simplex virus (HSV) is limited, especially with regard to reactivation and recurrent disease. To further explore the pathogenesis of ACV-resistant HSV-2 viruses, we used the guinea pig model of genital HSV-2 infection to evaluate several ACV-resistant isolates of both thymidine kinase (Tk)-altered and Tk-deficient phenotypes obtained from HIV-infected patients. Two plaque-purified workpools from each isolate were initially evaluated. Each produced acute disease and at least one clinical recurrence. The two strains that produced the most severe primary disease and most recurrences, one Tk-deficient virus and one Tk-altered virus, were further evaluated and shown to produce acute and recurrent genital disease similar to that seen with wild-type viruses. Furthermore, the reactivated virus producing recurrent lesions could be a pure population with minimal Tk activity. Finally, we showed that topical foscarnet treatment could alter disease and vaginal virus replication following vaginal inoculation with these two ACV-resistant strains. Using the guinea pig model of genital HSV-2 infection, we found that recurrent disease following infection with markedly Tk-deficient viruses was more common than expected, especially in select isolates. Furthermore, this model should be useful in evaluating potential new therapies for ACV-resistant HSV strains.

Plant products as topical microbicide candidates: assessment of in vitro and in vivo activity against herpes simplex virus type 2.

There is considerable interest in developing topical microbicides; products to be used intravaginally by women for protection against sexually transmitted diseases. Many compounds derived from plants have been shown to have antimicrobial properties. We examined 19 such compounds in vitro by plaque reduction assay to determine their activity against a common sexually transmitted pathogen, herpes simplex virus type 2. Compounds with an ED50 < or = 7.0 mg/ml were tested for efficacy in vivo. Four compounds, carrageenan lambda type IV, cineole, curcumin, and eugenol, provided significant protection (P < 0.05) in a mouse model of intravaginal HSV-2 challenge. Eugenol, which provided the greatest protection in mice was also evaluated using the guinea pig model of genital HSV-2 infection where it also demonstrated significant protection. Based on these results, several plant-derived compounds appear to warrant further evaluation as potential microbicides.

Effect of undecylenic acid as a topical microbicide against genital herpes infection in mice and guinea pigs.

There is increasing interest in the use of topical microbicides to help prevent the spread of sexually transmitted diseases (STD). Undecylenic acid (UA), a monosaturated fatty acid, is the active ingredient in a number of over-the-counter (OTC) antifungal spray powders, that also exhibits in vitro antibacterial and antiviral activity, including herpes simplex virus (HSV) activity. We, therefore, evaluated UA as a topical microbicide against genital HSV infection using the murine and guinea pig models of genital herpes. Mice were administered a 20% solution of UA in polyethylene glycol (PEG) vehicle, vehicle alone or phosphate buffered saline (PBS) intravaginally immediately prior to vaginal challenge with HSV-2. Pre-treatment with UA decreased the number of mice that became infected (P < 0.001 vs. PBS or vehicle control), developed symptoms (P <0.001) or died (P <0.001). However, when treatment was extended to either 5 min prior to or after viral inoculation, protection was lost. Similar findings were found using the guinea pig model, where UA treatment completely prevented HSV-2 vaginal infection when given immediately prior to HSV-2 inoculation (P<0.001 vs. PBS or vehicle control). Thus, UA, an approved OTC medication, provided significant protection against HSV disease and infection only when applied immediately before viral inoculation, indicating that better formulations were needed to extend the duration of protection.

Role of polymorphonuclear leukocytes in resolution of HSV-2 infection of the mouse vagina.

A naturally occurring population of polymorphonuclear leukocytes (PMNs) was detected in the vaginal lumen of uninoculated mice. A large population of these cells also infiltrated the vaginal mucosa following intravaginal HSV-2 inoculation. We examined the role of PMNs in preventing infection of the vaginal mucosa, virus clearance, and limiting virus spread to the lumbosacral ganglia. Depletion of PMNs prior to HSV-2 inoculation did not increase the incidence of infection suggesting that the small population of resident PMNs was ineffective in preventing infection by a viral pathogen. Depletion of PMNs impacted virus clearance from the vagina over a range of HSV-2 doses resulting in significantly higher virus titers on days 4 through 6 after inoculation. Virus clearance was delayed in PMN-depleted immune mu MT mice suggesting that PMN involvement in HSV-2 clearance did not require specific antibody. PMN-depletion of non-immune mice increased virus spread to the sensory ganglia only in mice inoculated with high virus doses. Immunization of mice with an attenuated strain of HSV-2 protected the sensory ganglia against acute infection with a challenge strain. Although PMN depletion of immune mice significantly increased virus titers in the vagina, the incidence of acute virus replication in the sensory ganglia was not different than in control-treated immune mice suggesting that PMNs were not required for protection of the sensory ganglia in immune animals. Taken together, these results suggest that PMNs were involved in resolving genital HSV-2 infections, but played only a limited role in preventing HSV-2 spread to the sensory ganglia.

Congenital renal arteriovenous malformations.

Congenital renal arteriovenous malformations are rare, but their incidence are frequency of recognition are rising. Six cases of both cirsoid and idiopathic varieties are described. Patients were either asymptomatic or presented with gross hematuria and flank pain. Physical findings included hypertension, cardiomegaly, flank tenderness, and an abdominal bruit. IVP findings included filling defects in the renal pelvis from blood clots, irregular mucosal pattersn, or mass effect. Angiography demonstrated either single, simple, vascular channels or multiple, complex, varix-like communications. In both there was early filling of the renal vein, a normal caliber to the feeding artery and draining vein, and no displacement of parenchymal vessles. Asymptomatic patients required no treatment. Surgical procedures that spare renal parenchyma are preferred.