Open space, not reduced herbivory, facilitates invasion of a marine macroalga, implying it is a disturbance-mediated "passenger" of change

Sargassum horneri, a brown macroalga, recently invaded the California coast, including into critical foundational communities such as kelp (Macrocystis pyrifera) forests. Despite its rapid spread, empirical tests that evaluate mechanisms underlying S. horneri's invasion success are lacking. To fill this knowledge gap, we conducted three field experiments on temperate rocky reefs in southern California using growth as a proxy for invasion success. We first tested whether S. horneri success differed with herbivory strength and native diversity by conducting a 2-factor experiment varying site (with different baseline levels of urchin densities and native algal diversity) and urchin access. We found S. horneri growth only differed among urchin treatments and not sites. We then evaluated whether S. horneri could successfully invade established algal canopies as a driver or whether it required open space as a passenger via a 2-factor experiment varying S. horneri size (small, medium, large) and canopy type (S. horneri, kelp, -canopy). We found that all S. horneri sizes grew fastest when canopy was lacking and light was high and slower in both canopy habitats with lower light; overall, small S. horneri grew slowest. Finally, we evaluated whether herbivore consumption for native species could facilitate S. horneri's invasion by conducting a 2-factor experiment varying species (M. pyrifera, S. horneri) and herbivore access. We found uncaged algae were consumed and caged algae grew, but there was no difference between species. Taken together, our results suggest that S. horneri is a "passenger" invader that will take advantage of points in time and space where light is plentiful, such as when M. pyrifera is removed via disturbance. Further, our results suggest that herbivory and native algal diversity are likely not key determining factors of the invasion success of S. horneri.

Flip it and reverse it: Reasonable changes in designated controls can flip synergisms to antagonisms

Ecological systems are subjected to multiple stressors that can interact in complex ways resulting in "ecological surprises". We examine the pivotal role of 'control' assignment in the categorization of stressors into five classes: additive, +synergistic, -synergistic, +antagonistic, and -antagonistic. We demonstrate if an alternate treatment can reasonably be considered the experimental control, nonlinear interaction classifications change, both in sign (+/-) and in direction (synergistic/antagonistic). Further, switching of interaction classifications is not predictable as changing control can result in multiple possible alternate nonlinear classifications. To explore the magnitude of this problem, we evaluate publications gathered for a recent meta-analysis to 1) explore rationales for choice of controls and 2) quantify how frequently it is reasonable to reassign the control. We found controls were designated with a variety of implicit and explicit justifications, with two overall rationales: 1) controls based on 'natural' conditions (historic, current, or future); 2) controls based on direction of impact, such that stressors always have negative impacts. We reasoned that control re-assignment was justified if an alternate treatment met one of these rationales. Of the 844 interactions classified in the meta-analysis, we determined >95% could be reassigned. Based on these findings, we recommend a new approach to meta-analyses, where the 'control' is strictly and consistently defined by the authors of the meta-analysis. These controls should be based on their broader question, rather than following the common practice of defaulting to controls assigned by the authors of each study, as we found these rationales vary broadly based on the specific questions of each study. Consistent control designation within the ecological or toxicological framework of each meta-analysis may provide deeper and more consistent insight into the nature of interactive effects between multiple stressors. Gaining this insight is crucial because stressor interactions are certain to increase in the Anthropocene.

Growth promoting hormonal implant pellets coated with a polymeric, porous film promote weight gain by grazing beef heifers and steers for up to 200 days

Two studies evaluated growth promoting effects of implant pellets (IP), each containing 3.5 mg estradiol benzoate (EB) and 25 mg trenbolone acetate (TBA), to which a polymeric, porous coating was applied. Trial 1 evaluated performance of heifers (n = 70/treatment, initial BW = 188 ± 2.2 kg) and steers (n = 70/treatment, initial BW = 194 ± 2.2 kg) implanted subcutaneously in the ear with 0 (SC), 2 (2IP), 4 (4IP), or 6 (6IP) pellets that delivered EB/TBA (mg/mg) doses of 0/0, 7/50, 14/100, and 21/150, respectively, over grazing periods of 202 d (heifers) or 203 d (steers). Animals received experimental treatments on d 0 and over the grazing period were managed as single groups by sex in a rotational grazing system. When pasture forage availability became limited, cattle were supplemented with preserved forage but not concentrate supplements. Weight gains by heifers treated with 2IP, 4IP, and 6IP were greater (P < 0.05) than SC heifers but not different from each other. Weight gains by steers treated with 2IP, 4IP, and 6IP were greater than SC steers (P < 0.05), and ADG by steers treated with 6IP was greater (P < 0.05) than steers given 2IP or 4IP. Trial 2 was a multisite grazing study performed with heifers and steers to compare ADG after treatment with one 6-pellet, coated implant delivering 21 mg EB and 150 mg TBA (6IP) to sham treated negative controls (SC) over a grazing period of at least 200 d. A completely random design was used at each site, with the goal to treat 70 cattle per site, treatment, and sex; data were pooled across sites. Heifers (n = 558, initial BW = 229 ± 16 kg) and steers (n = 555, initial BW = 235 ± 20 kg) grazed in rotational programs consistent with regional practices for an average of 202 d. When necessary, cattle were supplemented with preserved forage, but no concentrate supplements were fed. Over 202 d, ADG by heifers treated with 6IP was 11.3% greater (P = 0.0035) than SC heifers (0.64 ± 0.06 kg/d), and ADG by steers treated with 6IP was 17.2% greater (P = 0.0054) than SC steers (0.66 ± 0.08 kg/d). In neither study was there evidence that concurrent therapeutic treatments or abnormal health observations were influenced by experimental treatments. These studies demonstrated that a 6-pellet implant with a polymeric, porous coating that delivers 21 mg EB and 150 mg TBA improved ADG by grazing heifers and steers for at least 200 d compared to sham-implanted negative controls.

Diagnostic Immunization with Bacteriophage ΦX 174 in Patients with Common Variable Immunodeficiency/Hypogammaglobulinemia

Purpose: Use of the T cell-dependent neoantigen bacteriophage ΦX 174 has been described since the 1960s as a method to assess specific antibody response in patients with primary immunodeficiencies. We reviewed a cohort of patients at Duke University Medical Center who received immunization with bacteriophage and report the clinical utility and safety of the immunization, as well as patient characteristics.

Methods: A retrospective chart review was performed of all Duke Immunology Clinic patients (pediatric and adult) who received immunizations with bacteriophage, from 1976 to 2012. Subjects were selected for inclusion if their diagnosis at the time of bacteriophage was either presumed or confirmed common variable immunodeficiency (CVID), hypogammaglobulinemia, transient hypogammaglobulinemia, or antibody deficiency unspecified. Follow up post-immunization was also recorded.

Results: One hundred twenty-six patients were identified, 36 adults and 90 pediatric patients. Diagnoses prior to bacteriophage were CVID (n = 100), hypogammaglobulinemia (n = 23), and antibody deficiency (n = 3). Post-immunization diagnoses were CVID (n = 65), hypogammaglobulinemia (n = 19), unknown (n = 23), no primary immune deficiency (n = 10), and other primary immunodeficiency (n = 9). Seventy-five patients had abnormal bacteriophage results, 37 were normal, and 14 were borderline. There were 257 recorded administrations of the immunization. Information was available on adverse reactions for 171 administrations. Fourteen immunizations were associated with minor adverse events. Nineteen patients stopped their immunoglobulin replacement therapy based on reported normal responses to immunization.

Conclusion: Bacteriophage ΦX 174 immunization is a safe, well-tolerated, and clinically useful method to assess antibody response in patients with suspected antibody-mediated immunodeficiencies, particularly those who are on immunoglobulin replacement therapy at the time of immunization.

The efficacy of eprinomectin extended-release injection against Hypoderma spp. (Diptera: Oestridae) in cattle

The efficacy of eprinomectin in an extended-release injection (ERI) formulation was determined in cattle harboring naturally acquired infestations of first- or second- and third-stage larvae of Hypoderma spp. in three studies conducted according to the same protocol in the USA (two studies) and Germany (one study). Thirty cattle sourced from herds with a history of Hypoderma infestation were included in each study. Cattle were formed into replicates of three animals each on the basis of pre-treatment anti-Hypoderma antibody titers. Within replicates each animal was randomly allocated to one of the following treatments: ERI vehicle (control) at 1 mL/50 kg bodyweight, administered once on Day 0; Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once on Day 0 (when larvae were expected to be first instars); or Eprinomectin 5% ERI at 1 mL/50 kg bodyweight (1.0 mg eprinomectin/kg), administered once when larvae were second or third instars (study dependent, Day 73, 119, or 140). Treatments were administered by subcutaneous injection in front of the shoulder. In all studies, emerging and/or expressed Hypoderma larvae were recovered, speciated, and counted and viability was determined. Eprinomectin LAI treatment was 100% (p<0.05) efficacious against first- and second- or third-stage larvae of Hypoderma bovis (two studies) and Hypoderma lineatum (one study). All animals accepted the treatment well. No adverse reaction to treatments was observed in any animal in any study.

Airways inflammatory and atopy-related responses in athletes

The prevalence of asthma and airway hyperresponsiveness (AHR) in highly trained endurance athletes is rising. The type of training (i.e. endurance, or speed and power) seems to influence the airway symptoms. High-intensity exercise and training might contribute to the development of asthma or AHR in athletes previously unaffected by these airway disorders. Repeated hyperventilation of unconditioned air, as well as air containing irritants and/or allergens has been suggested to cause thermal, mechanical, or osmotic airway trauma resulting in damage to the airway epithelium. Subsequent airway inflammatory responses may be responsible for the development of atopy-related symptoms in endurance athletes such as those observed in asthma and AHR. Eosinophils and neutrophils are the inflammatory cells that have been frequently observed to be elevated in the airways of endurance athletes. The trafficking of these cells to the airways may possibly be regulated by TH2 cytokines that are expressed in the airways in response to epithelial cell damage. In addition, these airway inflammatory responses may lead to airway remodelling similar to that which occurs in asthma. The effect of the exercise challenge itself may initiate airway atopy-related and inflammatory responses in endurance athletes. While the literature seems to support the role of local airway conditions and/or events in inducing atopy-related symptoms in athletes, it is proposed that alterations in the hormonal and/or cytokine milieu with intense competition and/or training may also play a role. South African Journal of Sports Medicine Vol. 18 (2) 2006: pp. 46-51

Changes in neutrophil count, creatine kinases and muscle soreness after repeated bouts of downhill running

Objective. A primary objective was to examine circulating neutrophil count after repeated bouts of downhill running. An additional aim was to determine creatine kinase (CK) levels during the initial 12 hours, after repeated DHRs. Design. Eleven healthy, untrained Caucasian males performed 2 x 60 min bouts of DHR (-13.5%), spaced 14 days apart, at a speed equal to 75% VO2max on a level grade. Blood was collected before, after, and every hour for 12 hours, and every 24 hours for 6 days. Absolute neutrophil count, CK, and delayed-onset muscle soreness (DOMS) were assessed. Results were analysed using repeated measures ANOVA (p

Ergovaline-induced vasoconstriction in an isolated bovine lateral saphenous vein bioassay

Ergovaline has been proposed as a toxic component of endophyte-infected tall fescue. As many of the symptoms of fescue toxicosis are a result of compromised circulation, the objective of this study was to examine the vasoconstrictive potentials of ergovaline and a more documented ergopeptine, ergotamine, using a bovine, lateral (cranial branch) saphenous vein bioassay. Segments of the cranial branch of the lateral saphenous vein (2 to 3 cm) were collected from healthy, mixed breed cattle (n = 12 and n = 5 for the ergovaline and ergotamine experiments, respectively) at local abattoirs. The veins were trimmed of excess fat and connective tissue, sliced into 2- to 3-mm cross sections, and suspended in a myograph chamber containing 5 mL of a modified Krebs-Henseleit, oxygenated buffer (95% O2 + 5% CO2; pH = 7.4; 37 degrees C). The tissue was allowed to equilibrate at 1 g of tension for 90 min before of the addition of treatments. Increasing doses of ergovaline (1x10(-11) to 1 x10(-4) M) or ergotamine (1 x10(-11) to 1 x 10(-5) M) were administered every 15 min after buffer replacement. Contractile response data were normalized to a percentage induced by a reference dose of norepinephrine (1 x10(-4) M). Contractile responses of saphenous veins were similar for ergovaline and ergotamine. Initial contractile responses began at 1 x10(-8) M for both ergovaline and ergotamine (4.4 +/- 0.8% and 5.6 +/-1.1%, respectively). Vascular tension continued to increase as the alkaloid concentrations increased (maximums: 43.7 +/-7.1% at 1 x10(-5) M ergotamine; 69.6 +/- 5.3% at 1 x10(-4) M ergovaline). Interestingly, ergovaline-induced contractions (1 x10(-4) M) were not reversed by repeated buffer replacement over a 105-min period. As previously shown with ergotamine, these results confirm that ergovaline is a potent vasoconstrictor. The resistance of an ergovaline-induced contraction to relaxation over an extended period of time suggests a potential for bioaccumulation of this ergopeptine alkaloid and may aid in understanding its toxicity within the animal.

Assessment of vasoconstrictive potential of D-lysergic acid using an isolated bovine lateral saphenous vein bioassay

Vasoconstriction has been associated with several symptoms of fescue toxicosis thought to be alkaloid induced. Lysergic acid, an ergot alkaloid, has been proposed as a toxic component of endophyte-infected tall fescue. The objective of this study was to examine the vasoconstrictive potential of D-lysergic acid using a bovine lateral (cranial branch) saphenous vein bioassay. Before testing lysergic acid, validation of the bovine lateral saphenous vein bioassay for use with a multimyograph apparatus was conducted using a dose-response to norepinephrine to evaluate the effects of limb of origin (right vs. left) and overnight storage on vessel contractile response. Segments (2 to 3 cm) of the cranial branch of the lateral saphenous vein were collected from healthy mixed breed cattle (n = 12 and n = 7 for the lysergic acid and norepinephrine experiments, respectively) at local abattoirs. Tissue was placed in modified Krebs-Henseleit, oxygenated buffer and kept on ice or stored at 2 to 8 degrees C until used. Veins were trimmed of excess fat and connective tissue, sliced into 2- to 3-mm sections, and suspended in a myograph chamber containing 5 mL of oxygenated Krebs-Henseleit buffer (95% O2, 5% CO2; pH = 7.4; 37 degrees C). Tissue was allowed to equilibrate at 1 g of tension for 90 min before initiation of treatment additions. Increasing doses of norepinephrine (1 x 10(-8) to 5 x 10(-4) M) or lysergic acid (1 x 10(-11) to 1 x 10(-4) M) were administered every 15 min after buffer replacement. Data were normalized as a percentage of the contractile response induced by a reference dose of norepinephrine. Veins from both left and right limbs demonstrated contractions in a dose-dependent manner (P < 0.01) but did not differ between limbs. There were no differences in dose-response to norepinephrine between tissue tested the day of dissection and tissue tested 24 h later. Exposure of vein segments to increasing concentrations of lysergic acid did not result in an appreciable contractile response until the addition of 1 x 10(-4) M lysergic acid (15.6 +/- 2.3% of the 1 x 10(-4) M norepinephrine response). These data indicate that only highly elevated concentrations of lysergic acid result in vasoconstriction. Thus, in relation to the symptoms associated with vasoconstriction, lysergic acid may only play a minor role in the manifestation of fescue toxicosis.

Immunoglobulin responses to a repeated bout of downhill running

OBJECTIVE

To examine the effect of downhill running on immunoglobulin responses.

METHOD

Eleven untrained men performed 2 x 60 minute bouts of downhill running (-13.5% gradient), at a speed eliciting 75% of their vO2peak on a level grade. Two runs were spaced 14 days apart. Serum samples were collected before, after, and every hour for 12 hours and every 24 hours for six days. Serum total creatine kinase and immunoglobulin isotypes and subclasses were measured, and results were analysed using a repeated measures analysis of variance (12 hour period, 2 x 14; 24 hour intervals, 2 x 6, p < or = 0.05).

RESULTS

There was a significant interaction effect for creatine kinase (activity lower after run 2 than after run 1, 6-24 h) and exercise effect, with the serum concentrations of IgG1, IgG2, IgG4, and IgE lower, and IgM higher, after run 2.

CONCLUSION

Lower concentrations of IgG1, IgG2, and IgE after run 2 may reflect a dampened autoimmune inflammatory response to autoantigens and enhanced autoantigen clearance mediated by the upregulation of IgM.

Changes in Mucosal and Humoral Atopic-Related Markers and Immunoglobulins in Elite Cyclists Participating in the Vuelta a España

Atopic-related factors, humoral and mucosal immunoglobulins (Ig), and cortisol were measured in 17 professional cyclists competing in the 2003 Vuelta a España (a three-week multi-stage race). Venous blood and saliva samples were obtained the morning before the start of the race (T0), on the first rest day after 10 days of racing (T1), and before the start of the last stage after 21 days of racing (T2). Atopic-related factors, IgE, eosinophil cationic protein (ECP), and eosinophils, were significantly altered during the race. Serum IgE (T1: + 10 %) and ECP (salivary, T1: 113 % and serum, T2: 155 %) were significantly increased, while eosinophils (T1: - 32 %, T2: - 55 %) were significantly lower, than pre-race levels. Salivary sIgA secretion rate was significantly decreased at T2 (- 36 %). Pearson product-moment correlations revealed a modest correlation between salivary sIgA and salivary ECP (T1: r = 0.30; T2: r = 0.48; p < 0.01). Serum IgM, total IgG, IgG1, IgG2, IgA levels, at T1 and T2, and cortisol at T2, were significantly lower than pre-race levels. In conclusion, the elevation in IgE and ECP suggests an up-regulation of atopic-related factors in professional cyclists participating in the Vuelta a España. The correlation between salivary sIgA and salivary ECP indicates a role for sIgA in mediating mucosal inflammation. The alterations in Ig levels may indicate Ig isotype switching. An increasing state of hormonal fatigue may have influenced the observed immune alterations.

Dose determination of the persistent activity of moxidectin long-acting injectable formulations against various nematode species in cattle

The effectiveness, safety and production-enhancing benefit (improved weight gains) of moxidectin long-acting injection given subcutaneously in the ear at the rates of 0.75, 1.0 and 1.5mg/kg bw were evaluated in three studies under common protocol. The only adverse reaction to treatment was a mild (<2 tablespoons in volume), and for the most part transient (<28 days for the treatment rate of 1.0mg/kg bw) injection site swelling as noted in a minority of the animals (12.2% of the animals treated at the rate of 1.0mg/kg bw). Regardless of study site, post-treatment interval or dose rate, average daily gains were improved over control cattle by approximately 33%. Reductions in strongyle EPG counts relative to controls were > or = 90% for all dose rates of moxidectin for a post-treatment period of 42 days (Wisconsin), 84 days (Arkansas) and 140 days (Louisiana). In Arkansas and Louisiana, the majority (>80%) of post-treatment strongyle eggs, as determined by coproculture, were Cooperia spp. As determined by sequential necropsies, periods of continuous, post-treatment protection (> or = 90% efficacy in at least two out of three studies) for moxidectin long-acting injection given at the rate of 1.0 mg/kg bw were 90 days (adult Haemonchus spp.), 120 days (Dictyocaulus viviparus and adult Ostertagia and Oesophagostomum) and 150 days (Ostertagia spp. EL4).

Serum concentrations of C reactive protein, alpha1 antitrypsin, and complement (C3, C4, C1 esterase inhibitor) before and during the Vuelta a Espańa

OBJECTIVES

To determine serum concentrations of proinflammatory (C reactive protein, complement C3 and C4) and anti-inflammatory (alpha(1) antitrypsin, C1 esterase inhibitor (C1-INH)) acute phase proteins in elite cyclists before and during a three week cycle tour.

METHODS

Seventeen professional cyclists participating in the Vuelta a Espańa volunteered for the study. Their mean (SD) physical characteristics were: age 28 (1) years; height 1.7 (0.06) m; weight 65 (7) kg; body fat 7.6 (0.8)%; Vo(2)max 75.3 (2.3) ml/kg/min. Venepuncture was performed on each subject 24 hours before the tour began (T0), on day 11 (the first rest day; T1) and day 21 (the second to last stage of the tour; T2). Samples at T1 and T2 were taken about 17 hours after the previous stage. Analysis of variance was used to determine changes over time. Where significance was found, a Tukey post hoc test was performed.

RESULTS

C reactive protein concentrations were consistently within the normal range, although there was a 228%, non-significant increase at T1. C3 concentrations fell within the normal range at all times assessed. C4 concentrations before the race were within the normal range and were significantly increased 10 days (T1) into the race. C1-INH concentrations did not change significantly throughout the race. alpha(1) Antitrypsin concentration before the race was at the lower end of the normal range and was only significantly raised at T2.

CONCLUSIONS

Although not as pronounced as those reported in marathon/ultramarathon runners, elite cyclists participating in a three week cycle tour experienced increases in selected proinflammatory and anti-inflammatory acute phase proteins, indicating an acute phase/inflammatory response. It is tenable that the increase in alpha(1) antitrypsin and C1-INH (anti-inflammatory mediators) at T2 served to attenuate the acute phase/inflammatory response. The lower than normal resting concentrations of the acute phase proteins supports the notion that chronic aerobic exercise induces an anti-inflammatory state.

Airways inflammatory and atopy-related responses in athletes

The prevalence of asthma and airway hyperresponsiveness (AHR) in highly trained endurance athletes is rising. The type of training (i.e. endurance, or speed and power) seems to influence the airway symptoms. High-intensity exercise and training might contribute to the development of asthma or AHR in athletes previously unaffected by these airway disorders. Repeated hyperventilation of unconditioned air, as well as air containing irritants and/or allergens has been suggested to cause thermal, mechanical, or osmotic airway trauma resulting in damage to the airway epithelium. Subsequent airway inflammatory responses may be responsible for the development of atopy-related symptoms in endurance athletes such as those observed in asthma and AHR. Eosinophils and neutrophils are the inflammatory cells that have been frequently observed to be elevated in the airways of endurance athletes. The trafficking of these cells to the airways may possibly be regulated by TH2 cytokines that are expressed in the airways in response to epithelial cell damage. In addition, these airway inflammatory responses may lead to airway remodelling similar to that which occurs in asthma. The effect of the exercise challenge itself may initiate airway atopy-related and inflammatory responses in endurance athletes. While the literature seems to support the role of local airway conditions and/or events in inducing atopy-related symptoms in athletes, it is proposed that alterations in the hormonal and/or cytokine milieu with intense competition and/or training may also play a role. South African Journal of Sports Medicine Vol. 18 (2) 2006: pp. 46-51

Clearance of para-aminohippuric acid in wethers consuming locoweed

AIM

To validate the use of para-aminohippuric acid (PAH) as a marker for measuring blood flow in wethers consuming a mixed diet of locoweed and blue grama hay.

METHODS

Fourteen sheep, stratified by bodyweight (BW), were assigned to one of three treatments: 0.8 mg swainsonine (SW)/kg BW (HI), 0.2 mg SW/kg BW (LO), and no SW (Control). Sheep were fed various ratios of locoweed and blue grama hay to deliver SW treatments, for 28 days prior to infusion of PAH. Concentrations of SW and activities of alkaline phosphatase (Alk-P) and aspartate aminotransferase (AST) in serum were measured to confirm exposure to SW and subclinical intoxication. A single 20-ml injection of 5% PAH was delivered into the jugular vein after subclinical intoxication had been achieved. Blood samples were collected and serum analysed for PAH immediately prior to injection, then every 5 min from 5-30 min, and every 10 min from 30-60 min, following injection of PAH.

RESULTS

Effective delivery of SW was evident from the greater concentrations of SW measured in the serum of HI compared with LO animals (p<0.05). No significant differences were detected in the rate of elimination (range 0.097-0.108 L/min), elimination half-life (range 6.62-7.24 min), apparent volume of distribution for the central compartment (range 7.14-9.72 L), and clearance (range 0.73-0.92 L/min) of PAH, between treatments.

CONCLUSIONS

Subclinical intoxication with SW did not affect the pharmacokinetics of PAH. Thus, use of downstream dilution of PAH is a valid method to determine the rate of blood flow in nutrient flux experiments that involve consumption of locoweed.

Influence of ultra-endurance exercise on immunoglobulin isotypes and subclasses

BACKGROUND

Strenuous exercise is associated with tissue damage. This activates the innate immune system and local inflammation. Interaction between innate and adaptive immunity is essential for maintaining health, suggesting that the adaptive immune system may also be altered by exercise.

OBJECTIVES

To determine exercise induced changes in the adaptive immune system by measuring the immunoglobulin isotype and subclass response to an ultra-marathon.

METHODS

Venepuncture was performed on 11 experienced volunteers (six men, five women; mean (SD) age 43 (9.8) years) 24 hours before the projected finishing time and immediately after and 3, 24, and 72 hours after an ultra-marathon (90 km). Serum was stored at -80 degrees C. IgM, IgD, IgA, IgG, IgG1, 2, 3, and 4, and total IgE were measured.

RESULTS

The following immunoglobulins were significantly (p< or =0.05) altered after the race: IgD, immediately (-51%) and 24 hours (-41%) after; IgM 24 hours after (-23%); total IgG immediately after (+12%). There were no reports of symptoms of upper respiratory tract infections after the ultra-marathon.

CONCLUSIONS

In experienced ultra-endurance runners, alterations in immunoglobulin concentrations after a race suggest an enhanced immune response, including isotype switching, interactions with the innate immune system, and a secondary antibody response. These alterations may have a role in the maintenance of subject health after an ultra-marathon.

Non-allergic activation of eosinophils after strenuous endurance exercise

Objective. To determine the effect of prolonged endurance exercise on the serum concentrations of eosinophil cationic protein (ECP), immunoglobulin E (IgE) and upper respiratory tract symptoms (URTS). Design. In 11 healthy, experienced volunteers (6 males, 5 females, age 43 ± 9.8 years) the serum concentrations of ECP and IgE were measured, 24 hours prior to projected finishing time, immediately post exercise (IPE), and 3 h, 24 h, and 72 h after an ultramarathon (90 km). Self-reported URTS were also recorded for 14 days after the race. ECP was measured using radioimmunoassay and IgE using the Alastat Microplate Total IgE kit. The after-exercise values were corrected for plasma volume changes, which were calculated from haematocrit and haemoglobin values. Serum concentrations of ECP and IgE were analysed using an analysis of variance (ANOVA) comparing values with before-exercise levels. Level of significance was set at p ≤ 0.05. Results. ECP was significantly elevated at 72 hours (+52%), whilst IgE was not significantly altered after the ultramarathon. There were no reported URTS for the 14 days after the race. Conclusion. The eosinophil is a pro-inflammatory leukocyte involved in bronchial hyperreactivity and allergic inflammation of the airways. IgE is associated with allergic diseases such as asthma and rhinitis. Serum ECP is a sensitive marker of eosinophil activation. The result provides evidence for the non-allergic activation of blood eosinophils during prolonged endurance exercise. Whether this indicates exercise or environmentally induced airway inflammation, or a role for ECP in muscle /tissue repair, are hypotheses that require additional research. SA Sports Medicine Vol.16(2) 2004: 12-16

Alterations in acute-phase reactants (CRP, rheumatoid factor, complement, Factor B, and immune complexes) following an ultramarathon

Objectives. The human body initiates an acute phase response (APR) in response to a wide range of homeostatic disturbances. This complex series of reactions serves to activate repair processes and prevent ongoing tissue damage. An important aspect of the APR is the de novo synthesis of acute phase proteins (APP), many of which have not been thoroughly investigated. Main outcome measures. Alterations in CRP (C-reactive protein), C1est, C3, C4, C6, rheumatoid factor (RF) and Factor B were determined before and after an ultramarathon. Data were analysed using a one-way analysis of variance comparing values to pre-exercise levels. Significance was set at p < 0.05. Design. Venepunctures were performed on athletes participating in an ultramarathon (90 km) 24 hours before, immediately post-exercise (IPE), and 3h, 24h and 72h after the race. Serum was stored at –80°C until analysed. CRP levels in serum were assessed using the N Latex CRP kit. The levels of circulating immune complexes (CIC) were determined using particle-enhanced nephelometry. Complement proteins C1est, C3, C4 and RF were measured using laser nephelometry. C6 and Factor B were determined by radial immunodiffusion. Results. CRP was significantly elevated IPE (58%), 3h post (77%), 24h post (87%) and 72h post (69%). Pre-race CRP levels were above the normative range (5.10 ± 3.08 mg/l), C6 was significantly elevated (p < 0.05) at 24h post (7.8%) and 72h post (8.8%) exercise. Factor B was significantly elevated (p < 0.05) at 72h post exercise (12.8%). RF was significantly elevated at 72h post exercise (6.7%). Conclusion. Significant increases in selected acutephase reactants occur several days after the exercise event. In addition, as indicated by elevated resting levels of CRP, the athletes began the race with some degree of inflammation, presumably as a result of the cumulative training and racing mileage in preparation for the ultramarathon. SA Sports Medicine Vol.16(2) 2004: 17-21

Non-allergic activation of eosinophils after strenuous endurance exercise

Objective. To determine the effect of prolonged endurance exercise on the serum concentrations of eosinophil cationic protein (ECP), immunoglobulin E (IgE) and upper respiratory tract symptoms (URTS). Design. In 11 healthy, experienced volunteers (6 males, 5 females, age 43 ± 9.8 years) the serum concentrations of ECP and IgE were measured, 24 hours prior to projected finishing time, immediately post exercise (IPE), and 3 h, 24 h, and 72 h after an ultramarathon (90 km). Self-reported URTS were also recorded for 14 days after the race. ECP was measured using radioimmunoassay and IgE using the Alastat Microplate Total IgE kit. The after-exercise values were corrected for plasma volume changes, which were calculated from haematocrit and haemoglobin values. Serum concentrations of ECP and IgE were analysed using an analysis of variance (ANOVA) comparing values with before-exercise levels. Level of significance was set at p ≤ 0.05. Results. ECP was significantly elevated at 72 hours (+52%), whilst IgE was not significantly altered after the ultramarathon. There were no reported URTS for the 14 days after the race. Conclusion. The eosinophil is a pro-inflammatory leukocyte involved in bronchial hyperreactivity and allergic inflammation of the airways. IgE is associated with allergic diseases such as asthma and rhinitis. Serum ECP is a sensitive marker of eosinophil activation. The result provides evidence for the non-allergic activation of blood eosinophils during prolonged endurance exercise. Whether this indicates exercise or environmentally induced airway inflammation, or a role for ECP in muscle /tissue repair, are hypotheses that require additional research. SA Sports Medicine Vol.16(2) 2004: 12-16

Alterations in acute-phase reactants (CRP, rheumatoid factor, complement, Factor B, and immune complexes) following an ultramarathon

Objectives. The human body initiates an acute phase response (APR) in response to a wide range of homeostatic disturbances. This complex series of reactions serves to activate repair processes and prevent ongoing tissue damage. An important aspect of the APR is the de novo synthesis of acute phase proteins (APP), many of which have not been thoroughly investigated. Main outcome measures. Alterations in CRP (C-reactive protein), C1est, C3, C4, C6, rheumatoid factor (RF) and Factor B were determined before and after an ultramarathon. Data were analysed using a one-way analysis of variance comparing values to pre-exercise levels. Significance was set at p < 0.05. Design. Venepunctures were performed on athletes participating in an ultramarathon (90 km) 24 hours before, immediately post-exercise (IPE), and 3h, 24h and 72h after the race. Serum was stored at –80°C until analysed. CRP levels in serum were assessed using the N Latex CRP kit. The levels of circulating immune complexes (CIC) were determined using particle-enhanced nephelometry. Complement proteins C1est, C3, C4 and RF were measured using laser nephelometry. C6 and Factor B were determined by radial immunodiffusion. Results. CRP was significantly elevated IPE (58%), 3h post (77%), 24h post (87%) and 72h post (69%). Pre-race CRP levels were above the normative range (5.10 ± 3.08 mg/l), C6 was significantly elevated (p < 0.05) at 24h post (7.8%) and 72h post (8.8%) exercise. Factor B was significantly elevated (p < 0.05) at 72h post exercise (12.8%). RF was significantly elevated at 72h post exercise (6.7%). Conclusion. Significant increases in selected acutephase reactants occur several days after the exercise event. In addition, as indicated by elevated resting levels of CRP, the athletes began the race with some degree of inflammation, presumably as a result of the cumulative training and racing mileage in preparation for the ultramarathon. SA Sports Medicine Vol.16(2) 2004: 17-21

Effects of subcutaneous injections of a long acting moxidectin formulation in grazing beef cattle on parasite fecal egg reduction and animal weight gain

Trials were conducted in Arkansas, Idaho, Illinois and Wisconsin using a common protocol to evaluate effectiveness and safety of a long acting (LA), oil-based injectable formulation of moxidectin in beef cattle grazing spring and/or summer pastures. At each site, 150 cattle (steers and/or heifers) were blocked based on pretreatment fecal strongyle egg counts (EPG) and then randomly assigned to treatments within blocks. Presence of naturally acquired parasitic infections, confirmed by presence of parasite eggs in feces, was a prerequisite for study enrollment. Within each block of three animals, two received moxidectin LA injectable on day 0 at a dosing rate of 1.0 mg moxidectin/kg b.w. into the dorsal aspect of the proximal third of the ear, and one received a placebo control treatment. Cattle were weighed before treatment and on day 55 or 56 (55/56) after treatment. Fecal samples were also collected from 10 randomly selected blocks of animals at each site on days 14, 28 and 55/56 for EPG quantification. Average daily gain (ADG) was computed over the posttreatment period. Data pertaining to ADG and EPG were combined across sites and analyzed by mixed model analysis of variance to assess the fixed effect of treatment and random effects of site, block within site and the treatment by site interaction. Compared to placebo-treated controls, the geometric means of fecal EPG counts from cattle treated with moxidectin LA injectable were reduced 99.8% 14 days after treatment, 99.1% 28 days after treatment and 96.7% 55/56 days after treatment. Rate of weight gain by cattle treated with moxidectin LA injectable was 0.59 kg/day, or 23% (0.11 kg/day) more than placebo-treated controls (P<0.05). None of the cattle treated with moxidectin LA injectable exhibited signs of macrocyclic lactone toxicosis. Summarized across all study sites, proportions of cattle that received concurrent therapeutic treatments were similar among treatment groups. Study results demonstrate that moxidectin cattle LA injectable administered at a dosing rate of 1.0 mg moxidectin/kg b.w. to grazing beef cattle was effective and safe.

Heart rate recovery after exercise: a predictor of ventricular fibrillation susceptibility after myocardial infarction

Heart rate recovery after exercise, thought to be related to cardiac parasympathetic tone, has been shown to be a prognostic tool for all-cause mortality. However, the relationship between this variable and confirmed susceptibility to ventricular fibrillation (VF) has not been established. Therefore, myocardial ischemia was induced with a 2-min occlusion of the left circumflex artery during the last minute of exercise in mongrel dogs with myocardial infarction (n = 105 dogs). VF was induced in 66 animals (susceptible), whereas the remaining 39 dogs had no arrhythmias (resistant). On a previous day, ECG was recorded and a time-series analysis of heart rate variability was measured 30, 60, and 120 s after submaximal exercise (treadmill running). The heart rate recovery was significantly greater in resistant dogs than in susceptible dogs at all three times, with the most dramatic difference at the 30-s mark (change from maximum: 48.1 +/- 3.6 beats/min, resistant dogs; 31.0 +/- 2.2 beats/min, susceptible dogs). Correspondingly, indexes of parasympathetic tone increased to a significantly greater extent in resistant dogs at 30 and 60 s after exercise. These differences were eliminated by atropine pretreatment. When considered together, these data suggest that resistant animals exhibit a more rapid recovery of vagal activity after exercise than those susceptible to VF. As such, postexercise heart rate recovery may help identify patients with a high risk for VF following myocardial infarction.

Persistent activity of moxidectin long-acting injectable formulations against natural and experimentally enhanced populations of lice infesting cattle

A study was conducted under a common protocol in Wisconsin and Wyoming, USA, to evaluate therapeutic and persistent efficacy of two long-acting injectable formulations of moxidectin against lice populations infesting cattle. At each site, 30 beef calves were blocked into groups of three based on naturally acquired Linognathus vituli populations, then randomly assigned to treatments within blocks. Treatments, injected subcutaneously into the proximal third of the ear on Day 0, included saline, a long-acting oil-based formulation containing 10% moxidectin given at the rate of 1 mg moxidectin/kg body weight (M10/1.0), or a long-acting oil-based formulation containing 15% moxidectin given at the rate of 0.75 mg moxidectin/kg b.w. (M15/0.75). Species of sucking and chewing lice were quantified on nine predilection sites before treatment, then 28, 63, 98, 133 and 168 days after treatment. During intervals between lice counts after Day 28, study animals from the three treatment groups were commingled for 32 days with two lice-free sentinels plus four to six seeder calves with infestations of both sucking and chewing lice. Following each 32-day commingling interval, seeder and sentinel animals were removed, and principal animals were sorted into pens by treatment. Lice were quantified on sentinel animals on the day of removal, and lice were quantified on principal study animals 3 days after removal of sentinel and seeders. Moxidectin was generally not efficacious against Bovicola bovis in the injectable formulations tested, whereas Haematopinus eurysternus infestations were inadequate to judge product effectiveness. Based on geometric means, both M15/0.75 and M10/1.0 provided statistically significant therapeutic efficacy against existing infestations of L. vituli and Solenopotes capillatus (100% efficacy on Day 28), and provided persistent protection against reinfestation with L. vituli and S. capillatus (efficacy >97%) for at least 133 days following treatment.

Alterations in mood state following an ultra-marathon

SA Sports Medicine Vol.15(3) 2003: 29-31

Musculoskeletal manifestations of diabetes mellitus

Rheumatic complaints are common in patients with diabetes. Maintaining good glycaemic control by exercise, diet, and medication improves or prevents the development of rheumatic conditions.

Persistent efficacy of doramectin topical solution against induced infestations of Bovicola bovis and Solenopotes capillatus

A study was conducted in two locations, Wyoming and Wisconsin, USA, to evaluate the persistent efficacy of doramectin topical solution at a dose rate of 500 microg/kg body weight against artificially induced infestations of Bovicola bovis and Solenopotes capillatus on cattle. At each location, lice-free beef calves were individually housed and randomly allocated to treatment. Both B. bovis and S. capillatus were transferred from untreated donor animals to doramectin-treated cattle at the end of 35, 63, 91 or 126 day post-treatment periods. Cattle treated with a saline pour-on served as the control. Based on the geometric means of lice counts 2 weeks following transfer, the persistent efficacy of a single treatment with doramectin topical solution against induced infestations of B. bovis was 100.0, 100.0, 99.5, and 100.0% at post-treatment days of 35, 63, 91, and 126, respectively. Persistent efficacy against induced infestations of S. capillatus, for the same intervals, were 100.0, 94.9, 86.3, and 74.9%.

Immunization strategies to control a community-wide hepatitis A epidemic

One fifth of 527 cases of hepatitis A occurred in self-identified injection drug users during a community-wide epidemic in Spokane County (Washington) in 1997-8. We hypothesized that an immunization campaign targeted at illicit drug users could control the epidemic. Starting in May 1998, hepatitis A vaccine was provided to individuals in jails and other sites frequented by illicit drug users. Volunteers at vaccination sites were surveyed about risk. Serial convenience samples of jail inmates who denied previous vaccination were anonymously tested for hepatitis A virus (HAV) immunoglobulin G (IgG). From May to December 1998, 2765 high-risk individuals were vaccinated against hepatitis A. The proportion of HAV IgG seropositive inmates increased from 30% to more than 50%. Our findings suggest that vaccination along with naturally occurring infection increased the rate of hepatitis A immunity among illicit drug users during the final months of the epidemic. This supports the hypothesis that targeted immunization of high risk groups may shorten the natural history of a community-wide epidemic.

Comparison of carbohydrate and milk-based beverages on muscle damage and glycogen following exercise

This study examined effects of carbohydrate (CHO), milk-based carbohydrate-protein (CHO-PRO), or placebo (P) beverages on glycogen resynthesis, muscle damage, inflammation, and muscle function following eccentric resistance exercise. Untrained males performed a cycling exercise to reduce muscle glycogen 12 hours prior to performance of 100 eccentric quadriceps contractions at 120% of 1-RM (day 1) and drank CHO (n = 8), CHO-PRO (n = 9; 5 kcal/kg), or P (n = 9) immediately and 2 hours post-exercise. At 3 hours post-eccentric exercise, serum insulin was four times higher for CHO-PRO and CHO than P (p < .05). Serum creatine kinase (CK) increased for all groups in the 6 hours post-eccentric exercise (p < .01), with the increase tending to be lowest for CHO-PRO (p < .08) during this period. Glycogen was low post-exercise (33+/-3.7 mmol/kg ww), increased 225% at 24 hours, and tripled by 72 hours, with no group differences. The eccentric exercise increased muscle protein breakdown as indicated by urinary 3-methylhistidine and increased IL-6 with no effect of beverage. Quadriceps isokinetic peak torque was depressed similarly for all groups by 24% 24 hours post-exercise and remained 21% lower at 72 hours (p < .01). In summary, there were no influences of any post-exercise beverage on muscle glycogen replacement, inflammation, or muscle function.

Cytokine changes after a marathon race

The influence of carbohydrate (1 l/h of a 6% carbohydrate beverage), gender, and age on pro- and anti-inflammatory plasma cytokine and hormone changes was studied in 98 runners for 1.5 h after two competitive marathon races. The marathoner runners were randomly assigned to carbohydrate (C, n = 48) and placebo (P, n = 50) groups, with beverages administered during the races in a double-blind fashion using color codes. Plasma glucose was higher and cortisol was lower in the C than in the P group after the race (P < 0.001). For all subjects combined, plasma levels of interleukin (IL)-10, IL-1 receptor antagonist (IL-1ra), IL-6, and IL-8 rose significantly immediately after the race and remained above prerace levels 1.5 h later. The pattern of change in all cytokines did not differ significantly between the 12 women and 86 men in the study and the 23 subjects > or =50 yr of age and the 75 subjects <50 yr of age. The pattern of change in IL-10, IL-1ra, and IL-8, but not IL-6, differed significantly between the C and the P group, with higher postrace values measured for IL-10 (109% higher) and IL-1ra (212%) in the P group and for IL-8 (42%) in the C group. In conclusion, plasma levels of IL-10, IL-1ra, IL-6, and IL-8 rose strongly in runners after a competitive marathon, and this was not influenced by age or gender. Carbohydrate ingestion, however, had a major effect in attenuating increases in cortisol and two anti-inflammatory cytokines, IL-10 and IL-1ra.

Key challenges for toxicologists in the 21st century

The application of genomic technology to toxicology (toxicogenomics) has allowed the simultaneous identification of modified gene expression in response to a toxicant to be established for thousands of mammalian genes. This, together with the development of proteomics, metabonomics and our increasing understanding of individual human polymorphisms, will enable toxicologists in the next century to identify those individuals at particular risk from specific toxins, pesticides and pharmaceutical drugs. However, these new opportunities will prove fruitless unless toxicologists address some of the major issues that presently confront their discipline. If anything, the new technologies impose a greater demand on toxicologists to exercise expert judgement on the meaning of their data, and to apply 'common sense' when balancing risks and benefits.

Short-term dosing of alpha-hydroxytamoxifen results in DNA damage but does not lead to liver tumours in female Wistar/Han rats

It is now generally accepted that activation of tamoxifen occurs as a result of metabolism to alpha-hydroxytamoxifen. In this study, alpha-hydroxytamoxifen was given to female Wistar/Han rats (0.103 or 0.0103 mmol/kg, intraperitoneally, daily for 5 days). This resulted in liver DNA damage, determined by (32)P-post-labelling, of 3333 +/- 795 or 343 +/- 68 adducts/10(8) nucleotides, respectively (mean +/- SD, n = 4). Following HPLC separation, the retention times of the major alpha-hydroxytamoxifen DNA adducts were similar to those seen following the administration of tamoxifen. However, after rats were treated with alpha-hydroxytamoxifen (0.103 mmol/kg) for 5 days and the animals kept for up to 13 months, no liver tumours developed (0/7 rats), even with phenobarbital promotion (0/5 rats). GST-P foci were detected in the liver, but only after 13 months was their number or area significantly increased over the corresponding controls. When alpha-hydroxytamoxifen was given to female lambda/lacI transgenic rats (0.103 mmol/kg orally for 10 days) and the animals killed 46 days later, there was an approximate 1.8-fold increase in mutation frequency but no significant increase in G:C to T:A transversions as described after tamoxifen treatment. It is concluded that DNA damage alone, resulting from the short-term administration of alpha-hydroxytamoxifen, is not sufficient to initiate liver tumours even with phenobarbital promotion. As with tamoxifen, long-term exposure may be required to allow promotion and progression of transformed cells.

Pathogenicity Assessment of Puccinia lygodii, a Potential Biological Control Agent of Lygodium japonicum in Southeastern United States

Lygodium japonicum (Thunb.) Swartz (Family, Schizaeaceae) is naturally distributed from Asia to Australia and has naturalized in the United States from Texas to the Carolinas and Florida (4). Recently, it has been declared a Category I weed (the most invasive group) by the Florida Exotic Pest Plant Council. A foliar rust fungus was observed on a population of L. japonicum growing under the canopy of a pine/hardwood forest in Gainesville, FL. The lower surfaces of almost all the pinnules (foliage) were covered with cinnamon-brown eruptive pustules. Necrotic areas developed around mature, erupted, and coalesced pustules. Severely infected foliage were wilted and dried. Microscopic observations of the pustules and spore morphology revealed these eruptive structures to be uredinia. The dimensions (24.6 [+ 2.2] × 29.7 [+ 3.5] μm) and morphology (ellipsoid or obovoid, pale cinnamon-brown, and echinulate with indistinct pores) of urediniospore were similar to those reported for Puccinia lygodii (Har.) Arth. (Uredinales) (1). Therefore, the rust was identified as P. lygodii and confirmed by J. Hennen. P. lygodii is native to South America, where it has been recorded from L. volubile and L. venustum (2). This rust was previously identified as Milesia and Uredinopsis spp. on L. japonicum from Louisiana and Florida, respectively (3). Herein, we report the performance of Koch's postulates for P. lygodii on L. japonicum. Excised foliage bearing uredinia from plants collected near Gainesville were placed in a flask, flooded with deionized distilled water, shaken vigorously for a few minutes, and the suspension strained through four layers of cheesecloth. Urediniospores suspended in the filtrate were concentrated to 1.0 × 10⁶ spores/ml, using sedimentation technique, and then misted onto 3-week-old foliage of fully expanded fronds of four juvenile L. japonicum plants grown in pots, until the foliage were completely wet. The plants were then covered with a plastic bag and placed in dappled shade. After 3 days, the bags were removed and the water-filled containers were placed around L. japonicum plants to maintain high ambient humidity. During the remaining 4-week experimental period, the temperature and relative humidity under the shaded areas ranged from 23 to 38°C and 38 to 93%, respectively. The plants were monitored daily for development of symptoms characteristics of P. lygodii. Minute cinnamon-brown flecks appeared on the foliage 20 days after inoculation. Within 3 to 5 days, these flecked areas expanded, erupted, and formed uredinia on the lower surface of the symptomatic foliage. The morphology and size range of the uredinia and urediniospores were the same as those of the P. lygodii applied in this test. This is the first report confirming pathogenicity of P. lygodii on L. japonicum. P. lygodii may be a potential biological control agent of L. japonicum in the Southeast United States. References: (1) J. C. Arthur. Bull. Torrey Club 51:55, 1924. (2) J. F. Hennen and J. W. McCain. Mycologia 85:970-986, 1993. (3) J. W. McCain, J. F. Hennen, and Y. Ono. Mycotaxon 39:281-300, 1990. (4) R. W. Pemberton and A. P. Ferriter. Am. Fern J. 88:165-175, 1998.

Tamoxifen mutagenesis and carcinogenesis in livers of lambda/lacI transgenic rats: selective influence of phenobarbital promotion

Administration of tamoxifen (TAM) (20 mg/kg per day p.o.) for 6 weeks to female lambda/lacI transgenic rats caused a 4-fold increase in mutation frequency (MF) at the lacI gene locus in the livers of dosed animals compared with controls. After cessation of dosing, the MF showed a further increase with time at 2, 12 and 24 weeks, respectively. Phenobarbital promotion of similarly treated animals resulted in no increase in mutation frequency compared with TAM alone. Treatment with phenobarbital or TAM+phenobarbital resulted in time-dependent increases in liver weight compared with the corresponding controls. There was an increase in cell proliferation in the phenobarbital and TAM+phenobarbital groups, and at 24 weeks in the TAM dosed animals compared with controls. There was also a progressive increase in the number of GST-P expressing foci in the livers of TAM and TAM + phenobarbital rats compared with controls. The induction of cell proliferation and GSTP foci in the rat liver by phenobarbital is consistent with its ability to promote tamoxifen-initiated liver tumours in the rat. If the lacI gene is regarded as being representative of the rat genome in general (albeit that the gene is bacterial) the above observations suggest that promotion by tamoxifen confers selective advantage on mutated genes at loci that contribute to the tumour phenotype and that promotion of rat liver tumours by tamoxifen is not dependent simply upon the enhancement of cellular proliferation.

Mobile and localized protons: a framework for understanding peptide dissociation

Protein identification and peptide sequencing by tandem mass spectrometry requires knowledge of how peptides fragment in the gas phase, specifically which bonds are broken and where the charge(s) resides in the products. For many peptides, cleavage at the amide bonds dominate, producing a series of ions that are designated b and y. For other peptides, enhanced cleavage occurs at just one or two amino acid residues. Surface-induced dissociation, along with gas-phase collision-induced dissociation performed under a variety of conditions, has been used to refine the general 'mobile proton' model and to determine how and why enhanced cleavages occur at aspartic acid residues and protonated histidine residues. Enhanced cleavage at acidic residues occurs when the charge is unavailable to the peptide backbone or the acidic side-chain. The acidic H of the side-chain then serves to initiate cleavage at the amide bond immediately C-terminal to Asp (or Glu), producing an anhydride. In contrast, enhanced cleavage occurs at His when the His side-chain is protonated, turning His into a weak acid that can initiate backbone cleavage by transferring a proton to the backbone. This allows the nucleophilic nitrogen of the His side-chain to attack and form a cyclic structure that is different from the 'typical' backbone cleavage structures.

Susceptibility of elk to lungworms from cattle

Two studies were conducted to determine the infectivity of the lungworm, (Dictyocaulus viviparus) of cattle origin, in Rocky Mountain elk (Cervus elaphus nelsoni) or wapiti. In the first study, each of three 9-mo-old elk was administered 3,000 D. viviparus larvae from cattle using a nasogastric tube. In the second study, four 16-mo-old elk were each inoculated with 2,000 D. viviparus from cattle using a nasogastric tube. Elk were observed daily for signs of respiratory disease, and fecal samples were collected during the studies and evaluated for lungworm larvae using a modified Baermann technique. One elk was euthanatized during the patent period for recovery of adult lungworms, and three elk were euthanatized after larvae were no longer detected in feces. Lungworm larvae were not detected before inoculation in any of the 16-mo-old elk, but were detected 22 days after inoculation in one elk, 23 days after inoculation in two elk and 24 days after inoculation in all four elk. The prepatent period of this cattle isolate of D. viviparus in elk is therefore 22 to 24 days. The precise prepatent period was not determined in the three 9-mo-old elk, but larvae were detected in all three elk 25 days after inoculation. Numbers of larvae ranged from 1/ to 101/g feces with peak larval detection occurring 32 to 50 days after inoculation. Elk shed larvae from 22 to 83 days after inoculation, and patent periods of the parasite ranged from 24 to 62 days. Clinical signs of respiratory disease, with the exception of mild coughing after exercise, were not observed during the infections. Results from this experiment indicated that D. viviparus larvae of cattle origin can mature in elk and larvae can be passed in large numbers in feces, but this cattle isolate of D. viviparus was not highly pathogenic in elk.

Chemoprevention of breast cancer by tamoxifen: risks and opportunities

The antiestrogen tamoxifen is widely used in the adjuvant therapy of breast cancers in women and helps to prevent the occurrence of breast tumors in healthy women. However, epidemiological studies have shown tamoxifen treatment to be associated with a 2- to 5-fold increased risk of endometrial cancer. In rats but not in mice, long-term administration of tamoxifen results in an increase in hepatocellular carcinomas. Mechanistically, this occurs through metabolic activation of the drug, mainly by the CYP3A family, to an electrophilic species, that causes DNA damage in target tissues, and subsequently leads to gene mutations. It is controversial whether low levels of DNA damage occur in human uterine tissues, and there is no evidence that this can be causally related to the mechanisms of carcinogenesis. In healthy women, the risk:benefits for the use of tamoxifen is in part related to the risk of developing breast cancer. The results from the carcinogenicity studies in rats do not predict the likelihood that women will develop liver cancer or indeed cancers in other organs. The mechanism of endometrial cancer in women remains unresolved, but the experience with tamoxifen has highlighted the potential problems that need to be addressed in the assessment of future generations of selective estrogen receptor modulators.

Language lateralization and handedness in women prenatally exposed to diethylstilbestrol (DES)

Hand preferences and language lateralization were assessed in women exposed prenatally to the synthetic estrogen, diethylstilbestrol (DES), and in their unexposed sisters. The DES-exposed women showed an increased degree of hand preference (regardless of direction) and were more likely to be left handed for writing. However, the groups did not differ significantly on a dichotic listening measure of language lateralization. Perhaps as a result of the alterations in hand preferences, the typical relationship between hand preferences and language lateralization was disrupted in the DES-exposed group. Also, within the DES-exposed group, exposure early in gestation correlated with left handedness whereas exposure late in gestation correlated with reduced left ear (right hemisphere) scores on the verbal dichotic task. Results are discussed in terms of theoretical perspectives predicting hormonal influences on sexual differentiation of hemispheric asymmetry and in terms of separate critical periods for hormonal effects on individual sexually differentiated characteristics.

Cytokines and cell adhesion molecules associated with high-intensity eccentric exercise

Unaccustomed, eccentrically biased exercise induces trauma to muscle and/or connective tissue. Tissue damage activates an acute inflammatory response. Inflammation requires the effective interaction of different physiological and biological systems. Much of this is coordinated by the de novo synthesis of families of protein molecules, cytokines. The purpose of the present paper was to determine changes in blood levels of various cytokines in response to exercise-induced muscle damage that was effected using high-intensity eccentric exercise. Six healthy, untrained, college-age male subjects were required to perform the eccentric phase of a bench press and a leg curl (4 sets, 12 repetitions/set) at an intensity equivalent to 100% of their previously determined one-repetition maximum. Samples of blood were drawn at the following times: before exercise and 1.5, 6, 12, 24, 48, 72, 96, 120, and 144 h after exercise. These samples were analyzed for interleukins (IL): IL-1beta, IL-6, and IL-10; tumor necrosis factor-alpha; colony stimulating factors (CSF): granulocyte-CSF, macrophage-CSF, and GM-CSF; for cell adhesion molecules (CAM): P- and E-selectin, and intercellular cell adhesion molecule (ICAM-1), and vascular cell adhesion molecule (VCAM-1). Results were analyzed using a repeated-measures analysis of variance (P = 0.05). Compared to baseline values, IL-1beta was reduced (P = 0.03) at 6, 24, and 96-144 h after exercise; IL-6 was elevated (P = 0.01) at 12, 24, and 72 h after exercise; IL-10 was elevated (P = 0.009) between 72 and 144 h after exercise; M-CSF was elevated (P = 0.005) at 12 and 48-144 h after exercise; and P-selectin was reduced (P = 0.01) between 24 and 144 h after exercise. It is concluded that when high-intensity eccentric exercise is compared to strenuous endurance exercise, post-exercise changes in cytokines do occur, but they are generally of a smaller magnitude, and occur at a later time period after the termination of exercise.

Tissue distribution of 2-(2-nitro-4-trifluoromethylbenzoyl)-cyclohexane-1,3-dione (NTBC) and its effect on enzymes involved in tyrosine catabolism in the mouse

Administration of a single oral dose of 2-(2-nitro-4-trifluoromethyl-benzoyl)-cyclohexane-1,3-dione (NTBC) to mice increases the concentration of tyrosine in the plasma and aqueous humour. The tyrosinaemia is both time and dose-dependent with a single dose of 30 micromol NTBC/kg (10 mg/kg) producing maximal concentrations of tyrosine in plasma of about 1200 nmol/ml and in aqueous humour of about 2200 nmol/ml at 16 h after dosing. Analysis of the key hepatic enzymes involved in tyrosine catabolism, following a single dose of 30 micromol NTBC/kg, showed that 4-hydroxyphenylpyruvate dioxygenase (HPPD) was markedly inhibited soon after dosing and that the activity recovered very slowly. In response to the tyrosinaemia, the activity of hepatic tyrosine aminotransferase (TAT) was induced about two-fold, while the activity of hepatic homogentisic acid oxidase (HGO) was reduced at 4 and 5 days after dosing. Daily oral administration of NTBC at doses up to 480 micromol NTBC/kg (160mg/kg/day) to mice produced a maximal tyrosinaemia of about 600-700nmol/ml plasma, showing some adaptation relative to a single dose. Unlike the rat, no treatment-related corneal lesions of the eye were seen at any dose levels up to 6 weeks. Administration of a single oral dose of [14C]-NTBC at 30 micromol/kg led to selective retention of radiolabel in the liver and to a lesser extent the kidneys. Our studies show that NTBC is a potent inhibitor of mouse liver HPPD, which following repeat exposure produces a marked and persistent tyrosinaemia, which does not result in ocular toxicity.

Response of males and females to high-force eccentric exercise

It has previously been shown that females incur less muscle damage than males after strenuous exercise, but limited data are available for humans. To determine possible differences between the sexes in humans, the response to high-force eccentric exercise was examined in a large sample of women (n = 83) and men (n = 82). The participants performed a bout of eccentric exercise of the elbow flexors consisting of 70 maximal repetitions. Isometric strength, resting elbow angle and muscle soreness were measured before, immediately after (except soreness) and then daily for 7 days after exercise. There was a significant loss in strength among both groups (69% for women and 63% for men) (P < 0.01) immediately after exercise; at 168 h post-exercise, women still had a 27% strength loss and men had a 24% strength loss. No significant difference in strength loss or recovery rate was found between men and women. Soreness reached peak values 32-48 h post-exercise (P < 0.01), with no significant difference between men and women. Range of motion decreased significantly until 3 days after exercise (14.6 degrees or 0.255 rad loss for women; 12.2 degrees or 0.213 rad loss for men) (P < 0.01); at 168 h post-exercise, the women and men still showed a loss of 4.8 degrees (0.084 rad) and 4.0 degrees (0.07 rad), respectively. There was a significant interaction of sex x time (P < 0.01); a post-hoc test indicated that the women experienced a greater loss in range of motion at 72 h than men and this difference was maintained to 168 h post-exercise (P < 0.01). Thus, our results do not support the contention that women have a lower response to eccentric exercise than men.

Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress?

Overtraining syndrome (OTS) is a condition wherein an athlete is training excessively, yet performance deteriorates. This is usually accompanied by mood/behavior changes and a variety of biochemical and physiological alterations. Presently, there is no global hypothesis to account for OTS. The present paper will attempt to provide a unifying paradigm that will integrate previous research under the rubric of the cytokine hypothesis of overtraining. It is argued that high volume/intensity training, with insufficient rest, will produce muscle and/or skeletal and/or joint trauma. Circulating monocytes are then activated by injury-related cytokines, and in turn produce large quantities of proinflammatory IL-1beta, and/or IL-6, and/or TNF-alpha, producing systemic inflammation. Elevated circulating cytokines then co-ordinate the whole-body response by: a) communicating with the CNS and inducing a set of behaviors referred to as "sickness" behavior, which involves mood and behavior changes that support resolution of systemic inflammation: b) adjusting liver function, to support the up-regulation of gluconeogenesis, as well as de novo synthesis of acute phase proteins, and a concomitant hypercatabolic state; and c) impacting on immune function. Theoretically, OTS is viewed as the third stage of Selye's general adaptation syndrome, with the focus being on recovery/survival, and not adaptation, and is deemed to be "protective," occurring in response to excessive physical/physiological stress. Recommendations are made for potential markers of OTS, based on a systemic inflammatory condition.

The persistent efficacy of doramectin pour-on against biting and sucking louse infestations of cattle

A repeated-exposure challenge model was used to evaluate the pour-on formulation of doramectin in preventing the establishment of louse infestations in cattle. Twenty calves cleared of preexisting biting and sucking louse infestations were randomly and equally allocated to either a doramectin-treated or untreated control group, with five replicates per group. Doramectin pour-on was administered topically at a dose rate of 500 microg/kg body weight. Every 14 days, from a pool of seeder calves with infestations of at least 50 biting and 50 sucking lice each, 10 calves were selected and 1 was placed in each replicate pen. Every week during the 112-day study, 9 predilection sites on the doramectin-treated and untreated calves were examined to estimate the louse population density. A calf met the infestation criterion for a louse species when two or more live lice were counted on two or more body regions for two consecutive count days. Because only 4 of 10 untreated calves acquired Solenopotes capillatus infestations, the persistent efficacy of doramectin against S. capillatus was not evaluated. Bovicola bovis and Linognathus vituli infestations in the untreated calves developed shortly after exposure to infested seeder calves. The acquisition of B. bovis and L. vituli infestations in the doramectin-treated group was delayed for 77 days and 105 days, respectively.

Comparative hazards of chrysotile asbestos and its substitutes: A European perspective

Although the use of amphibole asbestos (crocidolite and amosite) has been banned in most European countries because of its known effects on the lung and pleura, chrysotile asbestos remains in use in a number of widely used products, notably asbestos cement and friction linings in vehicle brakes and clutches. A ban on chrysotile throughout the European Union for these remaining applications is currently under consideration, but this requires confidence in the safety of substitute materials. The main substitutes for the residual uses of chrysotile are p-aramid, polyvinyl alcohol (PVA), and cellulose fibers, and it is these materials that are evaluated here. Because it critically affects both exposure concentrations and deposition in the lung, diameter is a key determinant of the intrinsic hazard of a fiber; the propensity of a material to release fibers into the air is also important. It is generally accepted that to be pathogenic to the lung or pleura, fibers must be long, thin, and durable; fiber chemistry may also be significant. These basic principles are used in a pragmatic way to form a judgement on the relative safety of the substitute materials, taking into account what is known about their hazardous properties and also the potential for uncontrolled exposures during a lifetime of use (including disposal). We conclude that chrysotile asbestos is intrinsically more hazardous than p-aramid, PVA, or cellulose fibers and that its continued use in asbestos-cement products and friction materials is not justifiable in the face of available technically adequate substitutes.

Tamoxifen induces G:C-->T:A mutations in the cII gene in the liver of lambda/lacI transgenic rats but not at 5'-CpG-3' dinucleotide sequences as found in the lacI transgene

Tamoxifen, a rat liver carcinogen, can induce mutations in the lacI gene in the livers of lambda/lacI transgenic rats. However, the presence of persistent tamoxifen adducts on the liver DNA raises the possibility that some contribution to the mutagenesis from ex vivo mutations during the in vitro lacI assay cannot be ruled out. To address this issue, mutagenesis at the cII gene of the transgenic shuttle vector was determined using a selection based assay which is unaffected by the presence of tamoxifen-DNA adducts. Female lambda/lacI transgenic rats were dosed orally with tamoxifen (20 mg/kg body wt) daily for 6 weeks, causing a 3.2-fold increase in the mutant frequency (MF) in the cII gene compared with that obtained with solvent treated animals. This was similar to the MF found previously at the lacI gene and confirms that tamoxifen is mutagenic in vivo. The major class of mutation induced by tamoxifen in the cII gene was G:C-->T:A transversions as was found previously in the lacI gene. However, in the one unreplicated study of mutations in the p53 gene of liver tumours induced by tamoxifen, no G:C-->T:A transversions were found; possible differences between mutagenesis in normal and tumour tissues are explored. The major proportion of the G:C-->T:A transversions occurred at 5'-CpG-3' dinucleotide (CpG) sites in the lacI gene, but not at such sites in the cII gene. The methylation of CpG sites greatly enhances the targeting of deoxyguanosine by carcinogens, thus this finding might be explained by differences in the methylation patterns at their respective CpG sites; however, nothing is known about the methylation status of either the lacI nor the cII gene in this transgenic rat. This study raises the important issue of which target genes (mammalian or transgenic) should be used as endpoints in mammalian mutagenesis assays.