Increased SERCA2a sub-cellular heterogeneity in right-ventricular heart failure inhibits excitation-contraction coupling and modulates arrhythmogenic dynamics.

The intracellular calcium handling system of cardiomyocytes is responsible for controlling excitation-contraction coupling (ECC) and has been linked to pro-arrhythmogenic cellular phenomena in conditions such as heart failure (HF). SERCA2a, responsible for intracellular uptake, is a primary regulator of calcium homeostasis, and remodelling of its function has been proposed as a causal factor underlying cellular and tissue dysfunction in disease. Whereas adaptations to the global (i.e. whole-cell) expression of SERCA2a have been previously investigated in the context of multiple diseases, the role of its spatial profile in the sub-cellular volume has yet to be elucidated. We present an approach to characterize the sub-cellular heterogeneity of SERCA2a and apply this approach to quantify adaptations to the length-scale of heterogeneity (the distance over which expression is correlated) associated with right-ventricular (RV)-HF. These characterizations informed simulations to predict the functional implications of this heterogeneity, and its remodelling in disease, on ECC, the dynamics of calcium-transient alternans and the emergence of spontaneous triggered activity. Image analysis reveals that RV-HF is associated with an increase in length-scale and its inter-cellular variability; simulations predict that this increase in length-scale can reduce ECC and critically modulate the vulnerability to both alternans and triggered activity. This article is part of the theme issue 'The cardiomyocyte: new revelations on the interplay between architecture and function in growth, health, and disease'.

Effect of early photostimulation at 15-weeks of age and everyday spin feeding on broiler breeder performance.

To prevent broiler breeders from growing too quickly and becoming too large for optimum reproduction, their dietary intake is restricted. While current restricted feeding programs, such as skip-a-day feeding (SAD), improve the economic efficiency of broiler breeder operations, this management practice impacts bird welfare. There is an interest in finding strategies that could reduce the impact of feed restriction during broiler breeder rearing. This research investigated the effects of feeding pullets on an advanced growth curve for early photostimulation at 15 wk (15P) or standard growth curve for photostimulation at 21 wk (21P), using either an every-day-spin feeding program (EDS) or SAD feeding, on the reproductive parameters of broiler breeder hens in a 2 × 2 factorial arrangement. Overall, advancing the growth curve (15P) decreased blood corticosterone levels compared to 21P, but EDS resulted in higher blood corticosterone levels compared to SAD. At the end of rearing in both 15P and 21P, EDS pullets weighed less than SAD pullets. The onset of egg production was 20 and 24 wk of age for the 15P and 21P hens, respectively. Despite an earlier onset, 15P hens did not produce more eggs than 21P hens through 65 wk of age. Egg weight was reduced for 15P compared to 21P until 30 wk of age. The 15P hens had a greater number of double yolk eggs than the 21P hens. Fertility and hatch were not impacted by the advanced growth curve and early photostimulation. Although the current research indicates the potential to reduce feed restriction associated welfare issues by rearing broiler breeder pullets for an earlier photostimulation onset, further research in needed to determine if this management technique can be improved to optimize hen reproductive efficiency.

Dietary inclusion of AZOMITE improves feed efficiency in broilers and egg production in laying and broiler breeder hens.

The dietary inclusion of aluminosilicates has been reported to enhance pellet quality, improve feed mill throughput, bind toxins, improve feed efficiency, and promote immunological function across a variety of production systems. AZOMITE is a product marketed as a hydrated sodium calcium aluminosilicate containing macro and trace minerals, and rare earth elements and the potential benefits of its dietary inclusion in broiler, layer, and broiler breeder diets was investigated. In a battery study, broilers were fed diets containing 0, 0.125, 0.250, or 0.500% AZOMITE from 0 to 21 d of age. Laying hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from 54 through 98 wk of age, with the hens fed a standard molting diet or this diet supplemented with 0.25% AZOMITE from 71 to 72 wk of age. Broiler breeder hens were fed a control diet or this diet supplemented with 0.25% AZOMITE from the onset of photostimulation at 21 wk of age through 65 wk of age. All 3 dietary inclusion rates of AZOMITE improved (P < 0.05) the feed to body weight gain ratio in broilers fed these diets relative to broilers fed the control diet. In laying hens total marketable eggs, and in broiler breeder hens total settable eggs were increased (P < 0.05) with the dietary inclusion of AZOMITE by 8 eggs per hen. The inclusion of dietary AZOMITE also improved apparent Ca and P digestibility in broilers and tibia ash content in laying hens. The results indicate the dietary inclusion of AZOMITE in poultry diets improves bird performance.

Characterization of sperm-associated antigen 6 expression in the reproductive tract of the domestic rooster (Gallus domesticus) and its impact on sperm mobility.

Sperm mobility is a major determinant of sperm quality in the domesticated chicken (Gallus domesticus) and is therefore an area of interest for improving fertility. Sperm-associated antigen 6 (SPAG6) is an important flagellar protein implicated to be necessary for flagellar function but negatively associated with rooster fertility. This study was aimed to characterize the expression of SPAG6 and investigate its utility as a protein biomarker of sperm mobility. By western analysis, relative SPAG6 abundances were compared between the testicular, epididymal, and vasal tissues and in sequentially maturing sperm. Immunocytochemistry techniques were used to detect localization of SPAG6 in chicken sperm. Last, western analysis was used to compare relative SPAG6 abundances in sperm of differing mobility. SPAG6 was found in higher abundance in epididymal tissues and in highest abundance in vasal tissues, relative to that of the testis. SPAG6 was also found to sequentially increase in abundance in maturing sperm. SPAG6 localizes between the axonemal central pair of microtubules in the sperm flagella, but it is also found in lower concentration in the acrosomal region. SPAG6 was not a significant predictor of sperm mobility. SPAG6 abundance, alone, is not a strong predictor of sperm mobility. Its impact on rooster fertility is likely unrelated to its impact on sperm mobility.

Diffusion tensor imaging determines three-dimensional architecture of human cervix: a cross-sectional study.

OBJECTIVE: To determine the microarchitecture of the cervix using high-resolution diffusion tensor (DT) magnetic resonance imaging (MRI). DESIGN: Cross-sectional study. SETTING: Leeds, UK. SAMPLE: Women undergoing hysterectomy for benign pathology. METHODS: Ex-vivo DT-MRI measurements were obtained using a 9.4-T Bruker nuclear magnetic resonance (NMR) spectrometer on seven fixed human cervices obtained at hysterectomy. A deterministic fibre-tracking algorithm was used to indirectly visualise underlying fibre organisation. Inter-regional differences in tissue structure were sought using quantitative measurements of diffusion. MAIN OUTCOME MEASURE: The identification of an occlusive structure in the region corresponding to the internal cervical os. RESULTS: Fibre tracking demonstrated two regions: an outer circular and inner longitudinal layer. The total circumferential tract volume (TV) was greatest in the proximal region of the cervix (TV: proximal, 271 ± 198 mm3 ; middle, 186 ± 119 mm3 ; distal, 38 ± 36 mm3 ). Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) measurements were significantly different between regions in all samples (P < 0.0005), indicating greater tract density and organisation towards the internal os. CONCLUSION: Fibre tracking infers a system of dense, well-defined, encircling fibres in the proximal region of the cervix, corresponding to the location of the internal os. These findings may provide evidence of specific anatomic microarchitecture within the cervix able to resist intrauterine forces associated with pregnancy. TWEETABLE ABSTRACT: Diffusion-tensor MRI derived tractography identified well-defined encircling fibres at the internal os.

Zona pellucida protein B2 messenger ribonucleic acid expression varies with follicular development and granulosa cell location.

The freshly ovulated ovum in avian species is surrounded by a protein layer called the inner perivitelline layer (IPVL). The IPVL contains zona pellucida proteins and 6 distinct zona pellucida genes have been identified (ZPA, ZPB1, ZPB2, ZPC, ZPD and ZPX1) in the chicken. In the present research, the expression of the mRNA for ZPA, ZPB2, and ZPX1 was investigated in 2 lines of turkey hens selected for either increased egg production (E line) or increased body weight (F line). Theca and granulosa cell expression of the mRNA for ZPA and ZPB2 was also investigated in hierarchical and prehierarchical follicles from broiler breeder hens. Granulosa tissue was collected from F1 through F4 and F1 through F10 follicles in E line and F line hens, respectively. A one cm2 section of the granulosa layer around the germinal disc (GD) and an equivalent sized nongerminal disc (NGD) area was also collected from the F1 and F2 follicles from other hens from each genetic line. Granulosa and theca tissue was collected from hierarchical and prehierarchical follicles of broiler breeder hens. Total RNA was extracted from the samples. Minor groove-binding probes and primers for detecting ZPA, ZPB2, and ZPX1, were made for real-time PCR analyses. Expression of ZPA, ZPB2, and ZPX1 was detected in all follicle sizes from both genetic lines of hens. No significant differences in ZPA and ZPX1 mRNA expression were detected between the GD and NGD granulosa cells. However, the expression of the mRNA for ZPB2 was significantly greater in the GD granulosa cells when compared to the NGD granulosa cells in F1 and F2 follicles from E line and F line hens. In broiler breeder hens, the mRNA expression of ZPA and ZPB2 was greatest in the smallest prehierarchical follicles. The results suggest that higher expression of ZPB2 in the germinal disc area may be important for the preferential binding of sperm to this region of the IPVL.

Skeletal muscle VO2 kinetics from cardio-pulmonary measurements: assessing distortions through O2 transport by means of stochastic work-rate signals and circulatory modelling.

During non-steady-state exercise, dynamic changes in pulmonary oxygen uptake (VO2pulm) are dissociated from skeletal muscle VO2 (VO2musc) by changes in lung and venous O2 concentrations (CvO2), and the dynamics and distribution of cardiac output (CO) between active muscle and remaining tissues (Qrem). Algorithms can compensate for fluctuations in lung O2 stores, but the influences of CO and CvO2 kinetics complicate estimation of VO2musc from cardio-pulmonary measurements. We developed an algorithm to estimate VO2musc kinetics from VO2pulm and heart rate (HR) during exercise. 17 healthy volunteers (28 ± 7 years; 71 ± 12 kg; 7 females) performed incremental exercise using recumbent cycle ergometry (VO2peak 52 ± 8 ml min(-1) kg(-1)). Participants completed a pseudo-random binary sequence (PRBS) test between 30 and 80 W. VO2pulm and HR were measured, and CO was estimated from HR changes and steady-state stroke volume. VO2musc was derived from a circulatory model and time series analyses, by solving for the unique combination of venous volume and the perfusion of non-exercising tissues that provided close to mono-exponential VO2musc kinetics. Independent simulations showed that this approach recovered the VO2musc time constant (τ) to within 7% (R(2) = 0.976). Estimates during PRBS were venous volume 2.96 ± 0.54 L; Qrem 3.63 ± 1.61 L min(-1); τHR 27 ± 11 s; τVO2musc 33 ± 8 s; τVO2pulm 43 ± 14 s; VO2pulm time delay 19 ± 8 s. The combination of stochastic test signals, time series analyses, and a circulatory model permitted non-invasive estimates of VO2musc kinetics. Large kinetic dissociations exist between muscular and pulmonary VO2 during rapid exercise transients.

Towards a computational reconstruction of the electrodynamics of premature and full term human labour.

We apply virtual tissue engineering to the full term human uterus with a view to reconstruction of the spatiotemporal patterns of electrical activity of the myometrium that control mechanical activity via intracellular calcium. The three-dimensional geometry of the gravid uterus has been reconstructed from segmented in vivo magnetic resonance imaging as well as ex vivo diffusion tensor magnetic resonance imaging to resolve fine scale tissue architecture. A late-pregnancy uterine smooth muscle cell model is constructed and bursting analysed using continuation algorithms. These cell models are incorporated into partial differential equation models for tissue synchronisation and propagation. The ultimate objective is to develop a quantitative and predictive understanding of the mechanisms that initiate and regulate labour.

The mRNA for zona pellucida proteins B1, C and D in two genetic lines of turkey hens that differ in fertility.

The avian inner perivitelline layer (IPVL) contains zona pellucida protein-B1 (ZPB1), zona pellucida protein-C (ZPC) and zona pellucida protein-D (ZPD). These three proteins may be involved in sperm binding to the IPVL. ZPB1 is produced by the liver and transported to the developing preovulatory follicle, while ZPC and ZPD are synthesized and secreted by the granulosa cells of the preovulatory follicle. The mRNA of ZPB1, ZPC, and ZPD was investigated in two lines of turkey hens selected for over 40 generations for either increased egg production (E line) or increased body weight (F line). Total RNA was extracted from the liver and from 1cm(2) sections of the granulosa layer around the germinal disc and a nongerminal disc area of the F(1) and F(2) follicles of hens from each genetic line. Northern analysis was performed using chicken cDNA probes for all three ZP proteins. Hepatic mRNA for ZPB1 was greater (P<0.05) in turkey hens from the E line than the F line. Although, there was no difference in ZPC mRNA between the germinal disc and nongerminal disc region of the two largest follicles in E line hens, ZPC mRNA was greater in the nongerminal disc region compared to the germinal disc region in the two largest follicles obtained from the F line hens. There were no differences in ZPD mRNA between the germinal disc and nongerminal disc regions of the F(1) and F(2) follicles for either genetic line. The results suggest that the greater rates of fertility previously observed in eggs from the E line hens compared with the F line of hens may be related to differential amounts of the potential sperm binding proteins ZPB1 and ZPC.

Follicular development and expression of the messenger ribonucleic acid for the inhibin/activin subunits in two genetic lines of turkey hens that differ in total egg production.

The characterization of the follicular hierarchy and the expression of the mRNA for the inhibin/activin subunits was investigated in the follicles of 2 lines of turkey hens selected for over 40 generations for increased egg production (Egg line) or increased body weight (Growth line). The follicular hierarchies of 6 hens from the Egg and Growth lines were characterized in middle (45 wk of age) and late production (58 wk of age). Relative follicular weights for individual hierarchical follicles (>12 mm), pooled small yellow follicles (5 to 12 mm), and large white follicles (2 to 5 mm) were calculated. Total RNA was extracted for Northern blot analysis from individual granulosa cell layers of the F1 through F4 follicles, and from the combined granulosa and theca layers of small yellow follicles and large white follicles from an additional 6 hens from each genetic line. Egg line hens displayed a more distinct follicular size hierarchy than Growth line hens at 45 and 58 wk. Although total follicular weight relative to body size was greater at 45 and 58 wk of age for the Egg line hens than the Growth line hens, the total number of hierarchical follicles was greater in the Growth line hens at 45 and 58 wk of age. Expression of follistatin and the inhibin beta(B)-subunit was highest in nonhierarchical follicles, whereas the expression of the inhibin alpha- and beta(A)-subunits was highest in the hierarchical follicles. The inhibin alpha- and beta(A)-subunit mRNA expression pattern in the 4 largest follicles of the Growth line hens was not similar to the Egg line hens or characteristic of laying hens that have a high rate of egg production. The unusual inhibin subunit mRNA expression in the largest hierarchical follicles of the Growth line hens may account for their development of an abnormal follicular size hierarchy and for their poor egg production.

Influence of dietary fatty acid composition on cholesterol synthesis and esterification in hamsters.

To investigate the effects of dietary fat quality on synthesis and esterification of cholesterol, Syrian hamsters were fed diets containing corn, olive, coconut or menhaden oils (10% w/w) with added cholesterol (0.1% w/w). After 3 weeks, animals were sacrificed 90 min following IP injection of 3H2O. Synthesis of free cholesterol and movement of free cholesterol into ester pools were measured from 3H-uptake rate in liver and duodenum. Plasma total cholesterol and triglycerides levels were highest in coconut oil-fed animals, whereas hepatic total cholesterol and ester levels were elevated in olive oil-fed animals, as compared with all other groups. No diet-related differences were seen in duodenal cholesterol or total fatty acid content. In duodenum, uptake of 3H per g tissue into cholesterol was greater compared with liver; however, within each tissue, 3H-uptake into cholesterol was similar across groups. Notably, 3H-uptake into cholesterol ester in liver was highest in menhaden oil-fed animals. These data suggest that menhaden fish oil consumption results in enhanced movement of newly synthesized cholesterol into ester as compared with other fat types.