HLA B27 in Ankylosing Spondylitis: Differences in Frequency and Relative Risk in American Blacks and Caucasians.

Twenty-eight HLA alleles of the A and B loci were determined in 23 American Blacks and 50 Caucasians with primary ankylosing spondylitis (AS). The prevalence of HLA B27 was significantly increased in American Black patients (48 per cent) vs Black controls (two per cent), but was much less than the 94 per cent found in Caucasian patients (controls eight per cent). The lower prevalence of B27 in American Black patients vs Caucasian patients was significant (p < 0.001), and indicated that susceptibility to AS is not as closely associated with B27 in Blacks as in Caucasians. No other HLA antigen was significantly associated with AS in either racial group. Among B27 positive individuals, the relative risk of developing AS was significantly lower in American Blacks than in Caucasians. These data indicate that for diagnostic purposes, the absence of B27 is less important in ruling out AS in Blacks than in Caucasians.

Comparison of performance and carcass composition of a novel slow-growing crossbred broiler with fast-growing broiler for chicken meat in Australia.

Slow-growing broilers offer differentiation in the chicken meat market for consumers who have distinct preferences based on perceived higher welfare indices and willingness to pay a higher price for the product. Although breeding for slow-growing broilers is relatively advanced in Europe and the United States, it is limited in Australia. Crossbreeding is one of the approaches taken to developing slow-growing broiler strains. Thus, the aim of this study was to compare performance, immune response, leg health, carcass characteristics, and meat quality of a novel crossbred slow-growing broiler breed (SGB) with the conventional, fast-growing Cobb 500 broiler (CB) to assess their suitability as an alternative for chicken meat production in Australia. A total of 236 one-day-old broiler chicks (116 SGB and 120 fast-growing CB) were reared on standard commercial diet in an intensive production system. Birds and feed were weighed on a weekly basis and feed intake and feed conversion ratio calculated. At 21 d of age, a 2% suspension of sheep red blood cells was injected subcutaneously into 8 broilers of each breed to compare their antibody response. Birds from both breeds were grown to a final live weight of 2.0-2.2 kg, before a latency-to-lie (LTL) test, carcass analysis and apparent metabolizable energy (AME) assay were performed. The SGB reached the target weight at 55 d of age compared with 32 d in CB. However, SGB stood for longer during LTL, had higher thigh, drumstick, and wing yields (as a percentage of carcass weight) as well as darker and redder meat in comparison with the CB. The CB had better feed conversion efficiency, higher antibody (IgM) production, higher AME, heavier breast yield, and lower meat drip loss than the SGB. Although fast-growing CB outperformed the SGB for traditional performance parameters, the crossbred in this study was comparable with other slow-growing broiler breeds and strains across different countries and is thus a suitable candidate for a slow-growing alternative in Australia.

Changes to Cobb 500 chick characteristics, bone ash, and residual yolk mineral reserves during time spent in the hatcher.

Previous work has identified an effect of hatch time on chick femur mineralization. This experiment assessed the impact of hatch time and a 24-h post-hatch unfed time period on chick bone mineralization and yolk mineral utilization. In early hatching chicks, yolk Mg, Zn, K, P, Fe, and Cu decreased by 40 to 50% over the 24-h post-hatch unfed time period, whereas yolk Ca and Na decreased by 25 to 40% (P = 0.026). Yolk Sr was intermediate, decreasing by 37%. Late hatching chicks which had been hatched for no more than 30 h had a higher femur bone ash percentage compared to early hatching chicks which had spent over a 30-hour sojourn unfed in the incubator (P = 0.013). These results indicate that removing chicks from the incubator within 30 h of their hatch is likely to benefit their femoral mineralization.

Biomechanical impact testing of synthetic versus human cadaveric tibias for predicting injury risk during pedestrian-vehicle collisions.

Objective: The tibia is the most commonly fractured long bone in a pedestrian-vehicle collision. The standard injury assessment tool is the "legform," a device that mimics the human lower limb under impact loads. These devices are designed to identify the impact load that will cause the onset of injury, rather than replicate the type and severity of fracture. Thus, this study is the first to determine if composite tibias made by Sawbones (Pacific Research Labs, Vashon, WA, USA) designed for orthopedic biomechanics research, could also potentially be used for traffic safety research by simulating both the damage tolerance of human cadaveric tibias for peak force and bending moment and the fracture patterns themselves, thereby more accurately predicting injury type during real-world pedestrian-vehicle collisions.Methods: Synthetic tibias (n = 6) and human cadaveric tibias (n = 6) were impacted at midshaft at 8.3 m/s (i.e., 30 km/h) under 3-point bending using a pneumatic impacting apparatus. Fracture force, bending moment, and fracture patterns were compared between the two groups, and Weibull survivability curves generated for force and moment results, to identify injury risk thresholds.Results: There was no difference for synthetic vs. cadaveric tibias regarding impact force (4271+/-938 N vs. 4889+/-993 N, p = 0.44) or bending moment at fracture (275+/-64 Nm vs. 302+/-107 Nm, p = 0.69). Force-time curves for all tibias were similar in shape based on the first three Principal Components (p > 0.14). Weibull survivability curves had differences in shape and in the 10% risk of fracture limits, with force thresholds of 2873 N for the synthetic vs. 3386 N for the cadaveric, and bending moment limits of 180 Nm for the synthetic compared to 157 Nm for the cadaveric. All fracture patterns were clinically realistic, but not consistent between groups. The coefficient of variation for synthetic tibias was >0.2 for both peak force and bending moment, which precludes their use as a reproducible test surrogate for injury prediction.Conclusions: Synthetic composite tibias offer the potential for developing a frangible test surrogate, and matched cadaveric response in several respects. However, the repeatability was not high enough for them to be used in their present form for injury prediction.

The leg strength of two commercial strains of meat chicken subjected to different incubation profiles.

Lower egg shell temperatures (EST) during the first 2 weeks of incubation, notionally known as Slow start incubation, extended the standing time of a 5-week-old fast feathering meat chicken parent line. This study was designed to evaluate the effect of Slow start incubation on the standing ability of commercial meat chickens. Eggs from two strains of meat chickens, Strains 1 and 2, were incubated using either the Slow start incubation, (the initial EST was 36.75°C followed by a gradual increase in EST, reaching 37.8°C at day 16 of incubation), or Control incubation (EST 37.75°C to 38°C from the start of incubation until day 18 of incubation). Eggs were observed every 6 h from 468 h until 516 h of incubation to identify chick hatch window. At 516 h of incubation all chicks were taken out of the incubator (take-off). Chicks from each Strain and incubation treatment were randomly selected for assessment of chick weight, chick length, yolk sac weight, serum Ca and P, and femoral bone ash (BA). All unhatched eggs were inspected to determine the stage of embryo failure. Remaining chicks were grown for 5 weeks in floorpens. Weekly feed intake (FI), chick weight and feed conversion ratio (FCR) were determined. At 35 days of age the standing ability of visibly male birds was assessed in a latency-to-lie test. Compared to the Control, Slow start incubation delayed the average hatch time of both strains by ∼13 h, and reduced hatchability with 4.6% live but unhatched chicks, which was most evident in Strain 2. Significant differences due to main effects only were observed at take-off. Strain 1 chicks were significantly heavier and longer with higher serum Ca but significantly lower BA and serum P than Strain 2. Slow start incubation generated significantly heavier chicks that were shorter, but had significantly heavier yolk sacs, lower serum Ca but higher serum P than Control incubated chicks. During the 1st week post hatch Strain 1 Control incubated chicks had significantly higher FI and higher FCR than all other Strain and incubation treatments. At 35 days of age Slow start incubated birds of both Strains stood significantly longer than those from the Control incubation. This experiment clearly demonstrated the ability of Slow start incubation of commercial meat chickens to improve their leg strength.

Changes to mineral levels in the yolk of meat chicken embryos during incubation.

A total of 864 settable Cobb 500 eggs were used to explore changes in yolk mineral content during incubation. Eggs were individually weighed and then placed in a commercial incubator. On embryonic day (ED) 0, 6.5, 13.5, and 17.5, 36 eggs were sampled and yolk weight and mineral content were determined. The concentration of iron (Fe), phosphorus (P), and zinc (Zn) declined (P < 0.05) from ED0 to ED17.5. The concentration of calcium (Ca), magnesium (Mg), and strontium (Sr) increased (P < 0.05) from ED0 to ED17.5. The concentration of copper (Cu), potassium (K), and sodium (Na) increased initially (ED0 to ED6.5) but declined thereafter. There was no change (P > 0.05) in the concentration of yolk manganese (Mn) from ED0 to ED17.5. Substantial changes in yolk mineral concentration occur during incubation and are presumably associated with mobilization of shell reserves and flux between albumen and yolk. These data may be useful in designing in ovo interventions, optimizing meat chicken breeder premix formulation or assembly of suitable neonatal or pre-starter diets for meat chicken chicks.

A new method for determining levels of sedation in dogs: A pilot study with propofol and a novel neuroactive steroid anesthetic.

BACKGROUND: Different levels of consciousness are required in order to perform different medical procedures. Sedation scales established to objectively define various levels of sedation in humans have not been thoroughly characterized in non-human species. Postural changes in rats or dogs are useful as gross measures of sedation but are inadequate for quantitative assessment since graded levels of sedation are difficult to delineate and obscured by movement abnormalities. NEW METHOD: A new canine sedation scoring (CSS) method was developed based on the modified observer's assessment of alertness and sedation score (MOAA/S) used in humans. The method employed a combination of physical, auditory and somatosensory stimuli of increasing intensity. Cardiovascular, respiratory, and a neurophysiological measure of sedation (bispectral index: BIS) data were recorded. Validation studies were performed following intravenous loading and constant rate infusion of propofol or a novel synthetic neuroactive steroid (SGE-746). RESULTS: Four levels of consciousness were identified: 1) Awake, 2) Moderate Sedation (MS), 3) Deep Sedation (DS) and 4) General Anesthesia (GA). Cardiorespiratory measurements obtained after bolus administration of propofol and SGE-746 and at the end of each CRI remained within normal limits. Canine sedation scores correlated with BIS for SGE-746. SGE-746 exhibited a more gradual exposure-response relationship than propofol. Larger increases in the plasma concentration from awake values were required to achieve different levels of sedation with SGE-746 compared to propofol. COMPARISON WITH EXISTING METHODS: No other canine sedation scoring methods are widely accepted. CONCLUSION: A CSS method, based on the human MOAA/S scale defined four levels of consciousness in dogs and provided better resolution of sedation depth than BIS alone.

Incubation and hatch management: consequences for bone mineralization in Cobb 500 meat chickens.

From ~35 days of age fast growing meat chickens spend extended periods sitting or lying and less time standing. In a fast-feathering parent line lower early incubation temperatures which delayed chick hatch time, improved bone ash and extended their standing time. This incubation study assessed the consequences of incubation temperatures, hatch time and chick management at hatch/take off on femoral bone ash (BA) in Cobb 500 meat chickens. Embryos were incubated under either Control (between 37.8°C and 38.2°C egg shell temperature (EST)) or a Slow start (from 37.2°C at sett (the start of incubation), reaching 37.8°C EST at day 13 incubation), temperatures. Hatched chicks were identified at 492 h (20.5 days of incubation - classified as early (E)) or, between >492 and ⩽516 h (>20.5 and ⩽21.5 days of incubation - classified as late (L)), from setting. The E hatch chicks were allocated across three post-hatch treatments; treatment 1: E hatch chicks that were sampled E at 492 h from setting; treatment 2: E hatch chicks that were fed for a further 24 h in a floorpen before being sampled L at 516 h from setting; treatment 3: E hatch chicks that spent a further 24 h in the incubator before being sampled L at 516 h from setting. All L hatch chicks formed one treatment group which was sampled L at 516 h (i.e. L hatch chicks sampled L). It is not possible to sample L hatching chicks E hence this treatment is absent from the experimental design. Slow start incubation resulted in a higher total hatch percentage with a greater proportion of chicks hatching L, compared with the Control incubation. The L hatching chicks had significantly higher BA than the E hatching chicks. Of the E hatching chicks, those sampled both E and L had significantly lower BA than E hatching chicks fed for 24 h before L sampling. The E hatch, fed and sampled L chicks had the numerically highest BA, which was not significantly different from the BA of the L hatching chicks sampled L These results demonstrate that BA at hatch can be improved, either by extending the incubation period through a Slow start incubation profile, inducing L hatch, or alternatively, via the prompt provision of feed to E hatching chicks.

Effect of Intravenously Administered Crystalloid Solutions on Acid-Base Balance in Domestic Animals.

Intravenous fluid therapy can alter plasma acid-base balance. The Stewart approach to acid-base balance is uniquely suited to identify and quantify the effects of the cationic and anionic constituents of crystalloid solutions on plasma pH. The plasma strong ion difference (SID) and weak acid concentrations are similar to those of the administered fluid, more so at higher administration rates and with larger volumes. A crystalloid's in vivo effects on plasma pH are described by 3 general rules: SID > [HCO3-] increases plasma pH (alkalosis); SID < [HCO3-] decreases plasma pH (alkalosis); and SID = [HCO3-] yields no change in plasma pH. The in vitro pH of commercially prepared crystalloid solutions has little to no effect on plasma pH because of their low titratable acidity. Appreciation of IV fluid composition and an understanding of basic physicochemical principles provide therapeutically valuable insights about how and why fluid therapy can produce and correct alterations of plasma acid-base equilibrium. The ideal balanced crystalloid should (1) contain species-specific concentrations of key electrolytes (Na+ , Cl- , K+ , Ca++ , Mg++ ), particularly Na+ and Cl- ; (2) maintain or normalize acid-base balance (provide an appropriate SID); and (3) be isosmotic and isotonic (not induce inappropriate fluid shifts) with normal plasma.

Earlier hatching time predisposes Cobb broiler chickens to tibial dyschondroplasia.

Fertile eggs from Cobb 500 broiler breeder hens were incubated to provide low starting egg shell temperatures (EST; 36.9°C to 37.3°C) which were gradually increased to 37.8°C during the first 7 to 15 days of incubation compared with eggs incubated with a constant EST of 37.8°C (standard conditions) over the first 18 days of incubation. Time of individual chick hatching (measured at 6 h intervals from 468 h of incubation), chick weight, chick length and yolk weight were measured at take-off and BW was measured at 7, 14, 28, 34 and 42 days of age. Male birds at 34 and 42 days of age were assessed for their ability to remain standing in a latency-to-lie test. At 34 and 42 days, male birds were examined for leg symmetry, foot pad dermatitis, hock bruising and scored (scale 0 to 4, where 0=no lesion and 4=lesions extending completely across the tibial growth plate) for tibial dyschondroplasia (TD) lesions. The lower EST profiles caused chicks to hatch later than those incubated under the standard EST profile. Chicks which hatched at ⩽498 h incubation grew faster over the first 7 days than those that hatched later. There were significantly more birds (only males were studied) that hatched from the lower EST profiles with TD scores of 0 and 1 and fewer with score 4 at 34 days than those hatched under the standard profile. Male birds at 34 days with TD lesions ⩾3 stood for significantly shorter times than males with TD scores ⩽2. Moreover, male birds at 34 and 42 days with TD lesion scores of ⩾3 hatched significantly earlier and grew significantly faster over the first 2 weeks of age than did male birds with TD scores ⩽2. It appears possible to decrease the severity and prevalence of TD in the Cobb 500 broiler by ensuring that the birds do not hatch before 498 h of incubation.

Live and inactivated vaccine regimens against caecal Salmonella Typhimurium colonisation in laying hens.

OBJECTIVE: In Australia, Salmonella serovar Typhimurium (S. Typhimurium) is the predominant zoonotic serovar in humans and is frequently isolated from layer hens. Vaccination against this serovar has been previously shown to be effective in broilers and the aim of this current study was to assess and determine the best vaccination strategy (live or inactivated) to minimise caecal colonisation by S. Typhimurium. METHODS: A long-term experiment (56 weeks) was conducted on ISABROWN pullets using a commercial live aroA deleted mutant S. Typhimurium vaccine and an autogenous inactivated multivalent Salmonella vaccine (containing serovars Typhimurium, Infantis, Montevideo and Zanzibar). These vaccines were administered PO or by SC or IM injection, either alone or in combination. Pullets were vaccinated throughout rearing (to 18 weeks of age) and sequentially bled for antibody titre levels. The birds, vaccinated and controls, were challenged orally with a field isolate of S. Typhimurium at different ages, held for 21 days post-challenge, then euthanased and their caeca cultured for the presence of Salmonella. RESULTS: None of the oral live-vaccinated groups exhibited lasting protection. When administered twice, the inactivated vaccine gave significant protection at 17 weeks of age and the live vaccine given by SC injection given twice produced significant protection at 17, 25 and 34 weeks. CONCLUSIONS: Vaccination regimens that included parenteral administration of live or inactivated vaccines and thus achieved positive serum antibody levels were able to provide protection against challenge. Hence, vaccination may play a useful role in a management strategy for Salmonella carriage in layer flocks.

Influence of chick hatch time and access to feed on broiler muscle development.

The effect of hatch time and the timing of access to feed on growth rate and breast muscle development was assessed in Ross 308 broiler chickens. Chicks were removed from the incubator upon hatching, and classified as early (EH), midterm (MH), or late (LH) hatchers, based on the duration of their incubation. Feed and water were available either immediately at hatch, or 24 h after the conclusion of the hatch period. Hatchling body weight was uniform regardless of hatch time. Subsequently, bodyweight was increased in EH compared to LH birds following immediate access to feed, until 7 d in female, and 14 d in male birds. Relative breast weight was increased until 28 d in birds with immediate access to feed, and also EH and MH birds regardless of access to feed. Pectoralis major muscle morphology and expression of the myogenic regulatory factors myogenic determination factor 1 (MYOD1) and myogenin, and the proteoglycans syndecan-4, glypican-1, and decorin were measured. Myogenin and glypican-1 stimulate satellite cell (SC) differentiation. Glypican-1 expression was unaffected by treatment. A late increase in myogenin expression was observed in MH birds with delayed access to feed, and all LH birds. Syndecan-4 and MYOD1, expressed in proliferating SC, and decorin, which stimulates satellite cell proliferation and differentiation, were variably upregulated in the first wk posthatch in the same birds. These data suggest SC were activated and proliferating, but had reduced differentiation in later hatching and feed deprived birds. Conversely, EH birds with immediate access to feed had maximal myofiber width at 7 d, while fiber width was increased in birds with immediate access to feed compared to those with delayed access to feed through 40 d of age. These results demonstrate that delaying chick access to feed for 24 h upon removal from the incubator will impair muscle growth. Additionally, hatch time influences muscle development, with accelerated muscle growth in EH and MH, compared to LH birds, irrespective of access to feed.

Influence of hatch time and access to feed on intramuscular adipose tissue deposition in broilers.

The effect of hatch time and subsequent access to feed on intramuscular adipose tissue deposition was studied in the pectoralis major muscle of male Ross 308 broiler chickens. Based on their hatch time chicks were classified as early (EH), midterm (MH), or late (LH) hatchers, with an average incubation duration of 497.7 h for EH, 508.8 h for MH, and 514.5 h for LH birds. Chicks were provided access to feed either immediately at hatch, or 24 h after the conclusion of the hatch window. Expression of the adipogenic regulatory genes peroxisome proliferator-activated receptor gamma (PPARγ), and stearoyl-CoA desaturase (SCD), were measured at the time of hatch, and zero, one, 4, 7, 28, and 40 d. Intramuscular adipocyte cell width and visualization of adipose tissue deposition was observed at 28 and 40 d. Expression of PPARγ was increased in the pectoralis major of LH birds at the time of hatch, zero, and one d. The expression of PPARγ at one and 7 d, and SCD at 7 d were increased in all birds that received delayed access to feed. At 28 d, adipocyte cell width was increased in LH birds with delayed access to feed, compared to EH and MH birds with delayed access to feed and LH birds with immediate access to feed. At 40 d, adipocyte cell width was increased in all birds that received delayed access to feed. Also at 40 d, there was a trend (P = 0.078) for more extensive intramuscular adipose tissue deposition in LH than EH birds, and in birds with delayed access to feed (P = 0.075). These data indicate delayed access to feed increases intramuscular adipose tissue deposition in the pectoralis major muscle, and suggest that hatch time influences this regulation.

Oxygenation, oxygen delivery and anaesthesia in the horse.

Horses are the most difficult of the common companion animals to anaesthetise. Hypoxaemia or inadequate oxygen delivery to peripheral tissues during anaesthesia would seem a potential cause of increased mortality, but no direct link has been established. A number of methods of increasing oxygenation and oxygen delivery have been reported, with varying results and potential applicability. The purpose of this article is to review the literature with regard to oxygenation, oxygen delivery and methods to improve each and to make recommendations for clinical application.

Systematic differences in the response of genetic variation to pedigree and genome-based selection methods.

Genomic selection (GS) is a DNA-based method of selecting for quantitative traits in animal and plant breeding, and offers a potentially superior alternative to traditional breeding methods that rely on pedigree and phenotype information. Using a 60 K SNP chip with markers spaced throughout the entire chicken genome, we compared the impact of GS and traditional BLUP (best linear unbiased prediction) selection methods applied side-by-side in three different lines of egg-laying chickens. Differences were demonstrated between methods, both at the level and genomic distribution of allele frequency changes. In all three lines, the average allele frequency changes were larger with GS, 0.056 0.064 and 0.066, compared with BLUP, 0.044, 0.045 and 0.036 for lines B1, B2 and W1, respectively. With BLUP, 35 selected regions (empirical P < 0.05) were identified across the three lines. With GS, 70 selected regions were identified. Empirical thresholds for local allele frequency changes were determined from gene dropping, and differed considerably between GS (0.167-0.198) and BLUP (0.105-0.126). Between lines, the genomic regions with large changes in allele frequencies showed limited overlap. Our results show that GS applies selection pressure much more locally than BLUP, resulting in larger allele frequency changes. With these results, novel insights into the nature of selection on quantitative traits have been gained and important questions regarding the long-term impact of GS are raised. The rapid changes to a part of the genetic architecture, while another part may not be selected, at least in the short term, require careful consideration, especially when selection occurs before phenotypes are observed.

The effect of nutritional status on myogenic gene expression of satellite cells derived from different muscle types.

Satellite cells (SC) are a multipotential stem cell population responsible for facilitating posthatch muscle fiber hypertrophy. The proliferation and differentiation of SC is sensitive to nutritional regimen, and the SC response to nutrition varies depending upon their muscle type of origin. The objective of the current study was to determine the effect of altering protein synthesis on the expression of several key genes regulating SC activity and the effect of muscle type. Satellite cells isolated from the fast glycolytic pectoralis major and the fast oxidative and glycolytic biceps femoris were studied. These genes included the myogenic regulatory factors myogenic determination factor 1 (MyoD) and myogenin, the cell-membrane associated proteoglycans syndecan-4 and glypican-1, the extracellular matrix proteoglycan decorin, and the transcription factor paired box 7. Protein synthesis potential varied by the concentration of the sulfur amino acids Met and Cys during SC proliferation and differentiation. The SC were cultured and treated with 1 of 6 Met/Cys concentrations: 60/192, 30/96 (control), 7.5/24, 3.0/9.6, 1.0/3.2, or 0/0 mg/L. A consistent pattern of gene expression emerged following Met/Cys manipulation as increasing reductions in mRNA expression for all genes were observed as Met/Cys concentration decreased, whereas increased Met/Cys concentration caused either no change or had a small negative effect on mRNA expression. Reduced paired box 7 expression would limit myogenic specification of SC, whereas decreased myogenic regulatory factor expression would affect subsequent myogenic development of the SC. Decreased levels of decorin affect SC response to growth factors like myostatin and transforming growth factor ß, and extracellular matrix organization. These data highlight the importance of nutrition on the expression of genes critical for satellite cell activation, proliferation and differentiation, and growth factor signal transduction.

The effect of nutritional status and muscle fiber type on myogenic satellite cell fate and apoptosis.

Satellite cells (SC) are multipotential stem cells that can be induced by nutrition to alter their cellular developmental fate, which may vary depending on their fiber type origin. The objective of the current study was to determine the effect of restricting protein synthesis on inducing adipogenic transdifferentiation and apoptosis of SC originating from fibers of the fast glycolytic pectoralis major (p. major) and fast oxidative and glycolytic biceps femoris (b. femoris) muscles of the chicken. The availability of the essential sulfur amino acids Met and Cys was restricted to regulate protein synthesis during SC proliferation and differentiation. The SC were cultured and treated with 1 of 6 Met/Cys concentrations: 60/192, 30/96 (control), 7.5/24, 3/9.6, 1/3.2, or 0/0 mg/L. Reductions in Met/Cys concentrations from the control level resulted in increased lipid staining and expression of the adipogenic marker genes peroxisome proliferator-activated receptor gamma and stearoyl-CoA desaturase during differentiation in the p. major SC. Although b. femoris SC had increased lipid staining at lower Met/Cys concentrations, there was no increase in expression of either adipogenic gene. For both muscle types, SC Met/Cys, concentration above the control increased the expression of peroxisome proliferator-activated receptor gamma and stearoyl-CoA desaturase during differentiation. As Met/Cys concentration was decreased during proliferation, a dose-dependent decline in all apoptotic cells occurred except for early apoptotic cells in the p. major, which had no treatment effect (P < 0.05). During differentiation, decreasing Met/Cys concentration caused an increase in early apoptotic cells in both fiber types and no effect on late apoptotic cells except for an increase in the p. major 7.5/24 mg/L of Met/Cys treatment. In general, the viability of the SC was unaffected by the Met/Cys concentration except during proliferation in the p. major 0/0 mg/L of Met/Cys treatment, which increased SC viability. These data demonstrate the effect of nutrition on SC transdifferentiation to an adipogenic lineage and apoptosis, and the effect of fiber type on this response in an in vitro context.

Differential gene expression in laboratory strains of human head and body lice when challenged with Bartonella quintana, a pathogenic bacterium.

Human head and body lice are obligatory hematophagous ectoparasites that belong to a single species, Pediculus humanus. Only body lice, however, are vectors of the infectious Gram-negative bacterium Bartonella quintana. Because of their near identical genomes, yet differential vector competence, head and body lice provide a unique model system to study the gain or loss of vector competence. Using our in vitro louse-rearing system, we infected head and body lice with blood containing B. quintana in order to detect both differences in the proliferation of B. quintana and transcriptional differences of immune-related genes in the lice. B. quintana proliferated rapidly in body lice at 6 days post-infection, but plateaued in head lice at 4 days post-infection. RNAseq and quantitative real-time PCR validation analyses determined gene expression differences. Eight immunoresponse genes were observed to be significantly different with many associated with the Toll pathway: Fibrinogen-like protein, Spaetzle, Defensin 1, Serpin, Scavenger receptor A and Apolipoporhrin 2. Our findings support the hypothesis that body lice, unlike head lice, fight infection from B. quintana only at the later stages of its proliferation.