Existence of solutions for stress-rate type strain-limiting viscoelasticity in Gevrey spaces

In this work, we deal with a one-dimensional stress-rate type model for the response of viscoelastic materials, in relation to the strain-limiting theory. The model is based on a constitutive relation of stress-rate type. Unlike classical models in elasticity, the unknown of the model under consideration is uniquely the stress, avoiding the use of the deformation. Here, we treat the case of periodic boundary conditions for a linearized model. We determine an optimal function space that ensures the local existence of solutions to the linearized model around certain steady states. This optimal space is known as the Gevrey-class [Formula: see text], which characterizes the regularity properties of the solutions. The exponent [Formula: see text] in the Gevrey-class reflects the specific dispersion properties of the equation itself. This article is part of the theme issue 'Foundational issues, analysis and geometry in continuum mechanics'.

Abomasal infusion of essential fatty acids and conjugated linoleic acid during late pregnancy and early lactation affects immunohematological and oxidative stress markers in dairy cows

Oxidative stress and inflammation, as natural parts of metabolic adaptations during the transition from late gestation to early lactation, are critical indicators of dairy cows' metabolic health. This study was designed to investigate the effects of abomasal infusion of essential fatty acids (EFA), particularly α-linolenic acid, and conjugated linoleic acid (CLA) on plasma, erythrocyte, and liver markers of oxidative stress in dairy cows during the transition period. Rumen-cannulated German Holstein cows (n = 38) in their second lactation (11,101 ± 1,118 kg milk/305 d, mean ± standard deviation) were abomasally infused with one of the following treatments from d -63 antepartum until d 63 postpartum (PP): CTRL (n = 9; 76 g/d coconut oil); EFA (n = 9; 78 g/d linseed plus 4 g/d safflower oil); CLA (n = 10; isomers cis-9,trans-11 and trans-10,cis-12 CLA; 38 g/d); and EFA+CLA (n = 10; 120 g/d). Hematological parameters as well as markers of oxidative status were measured in plasma, erythrocytes, and liver before and after calving. Immunohematological parameters, including erythrocyte number, hematocrit, hemoglobin, mean corpuscular hemoglobin, leukocytes, and basophils, were affected by time, and their peak levels were observed on the day after calving. The oxidative stress markers glutathione peroxidase 1 and reactive oxygen metabolites in plasma and erythrocytes were both affected by time, exhibiting the highest levels on d 1 PP, whereas β-carotene, retinol, and tocopherol were at their lowest levels at the same time. Immunohematological parameters were only marginally affected by fatty acid treatment in a time-dependent manner. As such, lymphocyte and atypical lymphocyte counts were both significantly highest in the groups that received EFA at d 1 PP. Moreover, EFA supplementation increased the mean corpuscular volume and showed a trend for induction of mean corpuscular hemoglobin compared with the CLA group during the transition period. The PP mean thrombocyte volume was higher in the EFA than in the CLA group (except for d 28) and both EFA and CLA reduced number of thrombocytes and thrombocrit at distinct time points. Hepatic mRNA abundance of markers related to oxidative status, including glutathione peroxidase (GPX-1) and catalase (CAT), was lower (P < 0.05) in EFA-treated than non-EFA-treated cows at d 28 PP. Dairy cows at the onset of lactation were characterized by induced markers of both oxidative stress and inflammation. Supplementing EFA and CLA had minor and time-dependent effects on markers of oxidative stress in plasma, erythrocytes, and liver. A comparison of EFA supplementation with CLA or CTRL showed higher immunohematological response at d 1 PP and lower hepatic antioxidant levels by d 28 PP. Supplementation with EFA+CLA had only a minor effect on oxidative markers, which were more similar to those with the EFA treatment. Altogether, despite the time-dependent differences, the current findings show only minor effects of EFA and CLA supplementation in the prevention of early lactation-induced oxidative stress.

Pro-inflammatory Diet Pictured in Children With Atopic Dermatitis or Food Allergy: Nutritional Data of the LiNA Cohort

Background

Lifestyle and environmental factors are known to contribute to allergic disease development, especially very early in life. However, the link between diet composition and allergic outcomes remains unclear.

Methods

In the present population-based cohort study we evaluated the dietary intake of 10-year-old children and analyses were performed with particular focus on atopic dermatitis or food allergy, allergic diseases known to be affected by dietary allergens. Dietary intake was assessed via semi-quantitative food frequency questionnaires. Based on these data, individual nutrient intake as well as children’s Dietary Inflammatory Index (C-DII™) scores were calculated. Information about atopic manifestations during the first 10 years of life and confounding factors were obtained from standardized questionnaires during pregnancy and annually thereafter.

Results

Analyses from confounder-adjusted logistic regression models (n = 211) revealed that having atopic outcomes was associated with having a pro-inflammatory pattern at the age of 10 years: OR = 2.22 (95% CI: 1.14–4.31) for children with atopic dermatitis and OR = 3.82 (95% CI: 1.47–9.93) for children with food allergy in the first 10 years of life.

Conclusion

A pro-inflammatory dietary pattern might worsen the atopic outcome and reduce the buffering capacity of the individual against harmful environmental exposures or triggers. For pediatricians it is recommended to test for the individual tolerance of allergenic foods and to increase the nutrient density of tolerable food items to avoid undesirable effects of eating a pro-inflammatory diet.

Glucose metabolism and the somatotropic axis in dairy cows after abomasal infusion of essential fatty acids together with conjugated linoleic acid during late gestation and early lactation

Sufficient glucose availability is crucial for exploiting the genetic potential of milk production during early lactation, and endocrine changes are mainly related to repartitioning of nutrient supplies toward the mammary gland. Long-chain fatty acids, such as essential fatty acids (EFA) and conjugated linoleic acid (CLA), have the potential to improve negative energy balance and modify endocrine changes. In the present study, the hypothesis that combined CLA and EFA treatment supports glucose metabolism around the time of calving and stimulates insulin action and the somatotropic axis in cows in an additive manner was tested. Rumen-cannulated German Holstein cows (n = 40) were investigated from wk 9 antepartum (AP) until wk 9 postpartum (PP). The cows were abomasally supplemented with coconut oil (CTRL, 76 g/d); 78 g/d of linseed and 4 g/d of safflower oil (EFA); Lutalin (CLA, isomers cis-9,trans-11 and trans-10,cis-12 CLA, each 10 g/d); or the combination of EFA+CLA. Blood samples were collected several times AP and PP to determine the concentrations of plasma metabolites and hormones related to glucose metabolism and the somatotropic axis. Liver tissue samples were collected several days AP and PP to measure glycogen concentration and the mRNA abundance of genes related to gluconeogenesis and the somatotropic axis. On d 28 AP and 21 PP, endogenous glucose production (eGP) and glucose oxidation (GOx) were measured via tracer technique. The concentration of plasma glucose was higher in CLA than in non-CLA-treated cows, and the plasma β-hydroxybutyrate concentration was higher in EFA than in non-EFA cows on d 21 PP. The eGP increased from AP to PP with elevated eGP in EFA and decreased eGP in CLA-treated cows; GOx was lower in CLA than in CTRL on d 21 PP. The plasma insulin concentration decreased after calving in all groups and was higher in CLA than in non-CLA cows at several time points. Plasma glucagon and cortisol concentrations on d 21 PP were lower in CLA than non-CLA groups. The glucagon/insulin and glucose/insulin ratios were higher in CTRL than in CLA group during the transition period. Plasma IGF-I concentration was lower in EFA than non-EFA cows on d 42 AP and was higher during the dry period and early lactation in CLA than in non-CLA cows. The IGF binding protein (IGFBP)-3/-2 ratio in blood plasma was higher in CLA than in non-CLA cows. Hepatic glycogen concentration on d 28 PP was higher, but the mRNA abundance of PC and IGFBP2 was lower in CLA than non-CLA cows on d 1 PP. The EFA treatment decreased the mRNA abundance of IGFBP3 AP and PCK1, PCK2, G6PC, PCCA, HMGCS2, IGFBP2, and INSR at several time points PP. Results indicated elevated concentrations of plasma glucose and insulin along with the stimulation of the somatotropic axis in cows treated with CLA, whereas EFA treatment stimulated eGP but not mRNA abundance related to eGP PP. The systemic effects of the combined EFA+CLA treatment were very similar to those of CLA treatment, but the effects on hepatic gene expression partially corresponded to those of EFA treatment.

Changes in fatty acids in plasma and association with the inflammatory response in dairy cows abomasally infused with essential fatty acids and conjugated linoleic acid during late and early lactation

Dairy cows are exposed to increased inflammatory processes in the transition period from late pregnancy to early lactation. Essential fatty acids (EFA) and conjugated linoleic acid (CLA) are thought to modulate the inflammatory response in dairy cows. The present study investigated the effects of a combined EFA and CLA infusion on the fatty acid (FA) status in plasma lipids, and whether changes in the FA pattern were associated with the acute phase and inflammatory response during late pregnancy and early lactation. Rumen-cannulated Holstein cows (n = 40) were assigned from wk 9 antepartum to wk 9 postpartum to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 g/d of linseed oil and 4 g/d of safflower oil; ratio of oils = 19.5:1; n-6:n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; isomers cis-9,trans-11 and trans-10,cis-12; each 10 g/d), or both (EFA+CLA). Blood samples were taken to measure changes in FA in blood plasma on d -63, -42, 1, 28, and 56, and in plasma lipid fractions (cholesterol esters, free fatty acids, phospholipids, and triglycerides) on d -42, 1, and 56 relative to calving, and in erythrocyte membrane (EM) on d 56 after calving. Traits related to the acute phase response and inflammation were measured in blood throughout the study. Liver samples were obtained for biopsy on d -63, -21, 1, 28, and 63 relative to calving to measure the mRNA abundance of genes related to the inflammatory response. The concentrations of α-linolenic acid and n-3 FA metabolites increased in lipid fractions (especially phospholipids) and EM due to EFA supplementation with higher α-linolenic acid but lower n-3 metabolite concentrations in EFA+CLA than in EFA treatment only. Concentration of linoleic acid decreased in plasma fat toward calving and increased during early lactation in all groups. Concentration of plasma arachidonic acid was lower in EFA- than in non-EFA-treated groups in lipid fractions and EM. The cis-9,trans-11 CLA increased in all lipid fractions and EM after both CLA treatments. Plasma haptoglobin was lowered by EFA treatment before calving. Plasma bilirubin was lower in EFA and CLA than in CTRL at calving. Plasma concentration of IL-1β was higher in EFA than in CTRL and EFA+CLA at certain time points before and after calving. Plasma fibrinogen dropped faster in CLA than in EFA and EFA+CLA on d 14 postpartum. Plasma paraoxonase tended to be elevated by EFA treatment, and was higher in EFA+CLA than in CTRL on d 49. Hepatic mRNA abundance revealed time changes but no treatment effects with respect to the inflammatory response. Our data confirmed the enrichment of n-3 FA in EM by EFA treatment and the inhibition of n-3 FA desaturation by CLA treatment. The elevated n-3 FA status and reduced n-6:n-3 ratio by EFA treatment indicated a more distinct effect on the inflammatory response during the transition period than the single CLA treatment, and the combined EFA+CLA treatment caused minor additional changes on the anti-inflammatory response.

Changes in fluid and acid-base status of diarrheic calves on different oral rehydration regimens

The administration of oral rehydration solutions (ORS) is an effective method to treat dehydration and acidosis in calves suffering from diarrhea. The ORS can be prepared in water or milk. The aim of the present study was to elucidate how fluid and acid-base balance change after feeding milk compared with ORS prepared in water or milk to diarrheic calves. Calves (n = 30) with naturally acquired diarrhea were sequentially assigned in a 2:1 ratio to the following pretreatments: milk and water-ORS (pretreatment 1; n = 20 calves) or milk-ORS (pretreatment 2; n = 10 calves), respectively. The assignment was done on the day of diarrhea diagnosis. On d 3 ± 1 following assignment to pretreatment group, and after a fasting period of 9 h, diarrheic calves were subjected to the following treatments: 2 L of milk (pretreatment 1; n = 10 calves), water-ORS (pretreatment 1; n = 10 calves), or milk-ORS (pretreatment 2; n = 10 calves). Blood samples were taken before and at several time points until 6 h after feeding. Plasma protein, osmolality, and electrolytes were determined and a blood gas analysis was performed. Change in plasma volume was calculated according to plasma protein, and water intake during the experimental period was recorded. Plasma volume was increased 30 min after feeding water-ORS or milk but the increase was less pronounced after feeding milk compared with water-ORS. After feeding milk-ORS, no significant increase in plasma volume could be detected. Because of the pretreatment, plasma osmolality was higher in calves fed milk-ORS, but no change in plasma osmolality after feeding was detected. No difference in water consumption between the treatment groups was noted within the observed 6-h period. The pH was increased after feeding milk-ORS, whereas water-ORS and milk-feeding did not increase pH in blood. Pretreatment with milk-ORS resulted in higher baseline d-lactate concentration, but feeding milk-ORS reduced d-lactate values after feeding. In calves with diarrhea, plasma volume increased more quickly and to a greater extent after feeding water-ORS; thus, we recommend treating diarrheic calves with water-ORS before supplying milk. Nevertheless, diarrheic calves need milk to fulfill their energy needs. The administration of ORS in milk combined with free water access is more advisable than feeding milk exclusively because milk has no alkalinizing ability and contains less sodium. However, the effects of milk-ORS feeding on d-lactate levels in diarrheic calves need further elucidation.

Effects of abomasal infusion of essential fatty acids together with conjugated linoleic acid in late and early lactation on performance, milk and body composition, and plasma metabolites in dairy cows

Rations including high amounts of corn silage are currently very common in dairy production. Diets with corn silage as forage source result in a low supply of essential fatty acids, such as α-linolenic acid, and may lead to low conjugated linoleic acid (CLA) production. The present study investigated the effects of abomasal infusion of essential fatty acids, especially α-linolenic acid, and CLA in dairy cows fed a corn silage-based diet on performance, milk composition, including fatty acid (FA) pattern, and lipid metabolism from late to early lactation. Rumen-cannulated Holstein cows (n = 40) were studied from wk 9 antepartum to wk 9 postpartum and dried off 6 wk before calving. The cows were assigned to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 and 4 g/d; linseed/safflower oil ratio = 19.5:1; n-6/n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; BASF SE, Ludwigshafen, Germany; isomers cis-9,trans-11 and trans-10,cis-12 each 10 g/d) or EFA+CLA. Milk composition was analyzed weekly, and blood samples were taken several times before and after parturition to determine plasma concentrations of metabolites related to lipid metabolism. Liver samples were obtained by biopsy on d 63 and 21 antepartum and on d 1, 28, and 63 postpartum to measure triglyceride concentration. Body composition was determined after slaughter. Supplementation of CLA reduced milk fat concentration, increased body fat mass, and improved energy balance (EB) in late and early lactation, but EB was lowest during late lactation in the EFA group. Cows with CLA treatment alone showed an elevated milk citrate concentration in early lactation, whereas EFA+CLA did not reveal higher milk citrate but did have increased acetone. Milk protein was increased in late lactation but was decreased in wk 1 postpartum in CLA and EFA+CLA. Milk urea was reduced by CLA treatment during the whole period. After calving, the increase of nonesterified fatty acids in plasma was less in CLA groups; liver triglycerides were raised lowest at d 28 in CLA groups. Our data confirm an improved metabolic status with CLA but not with exclusive EFA supplementation during early lactation. Increased milk citrate concentration in CLA cows points to reduced de novo FA synthesis in the mammary gland, but milk citrate was less affected in EFA+CLA cows, indicating that EFA supplementation may influence changes in mammary gland FA metabolism achieved by CLA.

Stewart-Variablen des Säuren-Basen-Status bei Kälbern

Gegenstand und Ziel: Bisher wird das Stewart-Modell des Säuren-Basen- Status in der klinischen Veterinärmedizin kaum genutzt. Eine Ursache dafür ist der Mangel an Kenntnissen über anerkannte Referenzbereiche der Stewart-Variablen [strong ion difference = SID] und [Acid total = Atot] bei den verschiedenen Tierarten. Außerdem ist bisher wenig über den Einfluss wichtiger Erkrankungen auf die Stewart-Parameter bekannt. Material und Methode: Bei 17 Kälbern (Alter: 1–28 d) wurden statistisch begründete Referenzdaten für Serum-[SID3, 4] und -[Atot- Pro/-Alb] ermittelt. Außerdem wurde retrospektiv der Einfluss von Kälberdiarrhö auf die Stewart-Variablen im Experiment (39 Kälber; Alter: 5,3 ± 2,5 d) und in der klinischen Praxis (36 Kälber; Alter: 8,7 ± 5,0 d) untersucht. Ergebnisse: Gesunde Kälber besitzen in der ersten Lebenswoche mit der Serum-[SID3/4] von etwa 51/48 mmol/l um 2–3 mmol/l signifikant höhere Werte als ältere Tiere. Infolge des postnatalen Anstiegs der Serumalbuminkonzentration erhöhen sich die Serum-[Atot-Alb] von etwa 15 mmol/l (1. Tag) auf Werte von 22 mmol/l (28. Tag). Aus den Stewart-Variablen PvCO2, Serum-[SID4] und -[Atot-Pro] ließ sich der BlutpH mit der Differenz von 0,063 ± 0,0336 gegenüber den gemessenen Werten vorhersagen. Spontan auftretender Durchfall senkt bei Kälbern die Serum-[SID3, 4] auf etwa 40 mmol/l (überlebende Tiere) oder ante mortem auf noch niedrigere Werte. Schlussfolgerung: Die metabolische Azidose durchfallkranker Kälber ist nach dem Stewart-Modell auf die Imbalancen der starken Elektrolyte Na+ und Cl– (SID3↓), die Anhäufung von Blut-Laktat– (SID4↓) sowie die Dehydratation (Atot↑) zurückzuführen. Eine erfolgreiche Therapie der Azidose muss die erniedrigten Serum-[SID] anheben und durch Flüssigkeitszufuhr die Euhydratation mit physiologischer Serum-[Atot] herbeiführen. Klinische Relevanz: In oralen und parenteralen Rehydratationslösungen lassen sich die Werte für [SID] und [Atot] leicht ermitteln und zur prospektiven Wirksamkeitsbeurteilung der Lösungen gegen die Azidose bei durchfallkranken Kälbern nutzen.

Sea-level variations have influenced the demographic history of estuarine and freshwater fishes of the coastal plain of Paraná, Brazil

This study surveyed the mitochondrial haplotype diversity of nine freshwater fish species and two estuarine-marine species from the coastal basins and drainages of the highland plateaus of Paraná, Brazil. Portions of the cytochrome b gene or the control region were sequenced. The demographic history of each species was inferred using the Bayesian skyline method, mismatch distribution analysis and statistical neutrality tests. Demographic reconstruction analyses revealed a single pattern of variation in the effective population size (N_e ) among species. No dramatic changes in N_e were detected in upland species. By contrast, evidence of population expansion over the past 200 000 years was detected in all coastal plain and estuarine species. These findings correspond to periods of low sea-level (regressions) followed by a rapid increase in the sea-level by >100 m. The resulting reconnections and subsequent fragmentation and isolation between the estuarine and freshwater bodies were putatively relevant to the historical demography of the fish species in these areas.

Optical Characterization of Parathyroid Tissues

The parathyroid glands are small and often similar to lymph nodes, fat, and thyroid tissue. These glands are difficult to identify during surgery and a biopsy of the parathyroid for identification can lead to damage of the gland. The use of static and time-resolved fluorescence techniques to detect biochemical composition and tissue structure alterations could help to develop a portable, minimally invasive, and nondestructive method to assist medical evaluation of parathyroid tissues. In this study, we investigated 10 human parathyroid samples by absorbance, fluorescence, excitation, and time-resolved fluorescence measurements. Moreover, we compared the results of time-resolved fluorescence measurements with 59 samples of thyroid tissues. The fluorescence lifetimes with emission at 340 nm were 1.09 ± 0.10 and 4.46 ± 0.06 ns for healthy tissue, 1.01 ± 0.25 and 4.39 ± 0.36 ns for benign lesions, and 0.67 ± 0.36 and 3.92 ± 0.72 ns for malignant lesions. The lifetimes for benign and malignant lesions were significantly different, as attested by the analysis of variance with confidence levels higher than 87%. For each class of samples (healthy, benign, and malignant) we perceived statistical differences between the thyroid and parathyroid tissue, independently. After further investigations, fluorescence methods could become a tool to identify normal and pathological parathyroid tissues and distinguish thyroid from parathyroid tissues.

Northernmost record of the little gulper shark Centrophorus uyato in the north-eastern Atlantic Ocean, with taxonomical notes on Centrophorus zeehaani

A specimen of the little gulper shark Centrophorus uyato was collected in the Norwegian Sea off the coast of northern Norway, marking the northernmost record of the species in the eastern North Atlantic Ocean. Morphological characteristics collected from the specimen indicate a close relationship to the Australian species Centrophorus zeehaani. DNA barcoding analysis of the mitochondrial cytochrome oxidase subunit I (coI) gene for species of Centrophorus suggests conspecificity of C. uyato and C. zeehaani.

Evaluation of ketogenic vs. glucogenic substrates as energy sources in starter diets for Holstein dairy calves

Beiranvand, H., Khorvash, M., Ghorbani, G. R., Homayouni, A., Bachmann, L. and Kargar, S. 2014. Evaluation of ketogenic vs. glucogenic substrates as energy sources in starter diets for Holstein dairy calves. Can. J. Anim. Sci. 94: 717–723. The objective of this study was to investigate the influence of the inclusion of granular sugar and sodium propionate as ketogenic and glucogenic substrates, respectively, in calf starter diets on the performance, weaning age, rumen fermentation characteristics and plasma β-hydroxybutyrate (βHBA). Twenty-one newborn male Holstein calves were housed in individual pens until 10 wk of age, receiving starter ad libitum, fresh water free choice, and fed four liters of pasteurized waste milk daily until weaning. Calves were randomly assigned to one of the following treatments: (1) no supplemental additive (Control); (2) granular sugar (5% of dietary DM; Sugar); and (3) sodium propionate (5% of dietary DM; Propionate). Overall, no differences were observed among treatments for starter intake, average daily gain, feed efficiency, day of weaning, body weight at weaning and at the end of the study. Body measurements including body length, hip height, hip width, and heart girth were remained unchanged among treatments. Ruminal fluid pH (5.36 to 5.58) and concentrations of total volatile fatty acids (93.1 to 101.6 mM), acetate (43.6 to 53.1 mM), propionate (30.5 to 35.1 mM), and ratio of acetate to propionate (1.42 to 1.89) were not affected by treatments over the experimental period. However, the concentration of butyrate was greater at 35 and 70 d of age in calves receiving Sugar compared with calves receiving Propionate, but not compared with the Control. Greater blood βHBA at 45, 60 and 70 d of age was noticed in calves fed Sugar compared with those fed Control and Propionate. In conclusion, according to the concentrations of supplemental ketogenic and glucogenic substrates used in the current experiment, sugar and sodium propionate in starter diets did not improve calf performance.

Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation

PURPOSE

The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP).

METHODS

In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes.

RESULTS

Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2-100) and a specificity (13/20) of 65.0% (95% CI, 40.8-84.6).

CONCLUSIONS

AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP.

Dietary influences on the hydration and acid-base status of experimentally dehydrated dairy calves

The incorporation of oral rehydration solutions (ORS) into 'milk meals' is potentially an effective, time-saving method of treating diarrhoeic calves. Although milk-based ORS are effective in improving the hydration and acid-base status of healthy calves, this effect remains to be confirmed in dehydrated/diarrhoeic animals. In this study, six experimentally-dehydrated calves were fed with either milk replacer (MR) or an ORS prepared in either water (WORS) or MR (MORS). In one experiment, calves were not treated and blood samples were taken before and after feeding. Parameters of hydration status were determined and blood gas analysis was performed. Plasma volumes increased significantly following the intake of a 'fluid meal' whereas they remained constant in the absence of treatment. The rate of plasma volume expansion was reduced by the feeding of MR relative to WORS or MORS. In dehydrated calves, the expansion of plasma volume was more pronounced following the intake of WORS but the increase was less and plasma osmolality increased significantly following the ingestion of MORS. The acid-base status of animals improved as a result of fluid absorption, but this effect was less obvious as the experimental protocol resulted in severe dehydration and moderate acidosis. Feeding hypertonic MORS raised the plasma osmolality in dehydrated calves, and may increase the risk of hypernatraemia in diarrhoeic calves, which should therefore have ad libitum access to water when undergoing treatment with hypertonic ORS. Further research is planned to assess whether feeding ORS reconstituted in milk or MR combined with ad libitum access to water offers a practical treatment for diarrhoeic calves.

Response of plasma fatty acid profiles to changes in dietary n-3 fatty acids and its correlation with erythrocyte fatty acid profiles in dogs

An elevated level of long-chain n-3 fatty acids (FA) in tissue membranes has a positive influence on the progression and treatment of many diseases. Therefore, dietary supplementation of n-3 FA is recommended in some diseases. Even though n-3 FA are absorbed readily from the diet, their incorporation into tissues may be compromised in diseased animals. In a clinical setting, it is desirable to monitor the success of dietary intervention. Plasma FA as well as erythrocyte membrane (EM) FA can be used to monitor dietary FA intake. This study compares FA from EM and plasma with regard to their reaction time and reliability for monitoring dietary changes of tissue FA profiles in dogs. Thirty dogs were divided into three groups and fed for 12 weeks. The control group (CONT) was fed a commercial standard diet low in n-3 FA. One group received the standard diet and 85 mg/kg body weight of a docosahexaenoic acid (DHA) concentrate (ADD). The third group was fed a commercial dog food containing fish oil (FO), which is rich in eicosapentaenoic acid (EPA). EM and plasma FA profiles were analysed by GC separately. Data on EM FA were published recently. n-3 FA in plasma reached the new level after 2 weeks (8 weeks in EM). Dietary differences between DHA and EPA are obvious after 1 week already. The concomitant decrease in plasma n-6 FA differed between ADD and FO. In general, the correlation of n-6 FA between plasma and EM was low. We therefore conclude that analysis of plasma FA is sufficient for monitoring a diet-induced increase in tissue n-3 FA in dogs. However, EM FA should be analysed if the effect of dietary intervention on tissue n-6 FA is important.

Denning-area fidelity and mitochondrial DNA diversity of female polar bears (Ursus maritimus) in the Barents Sea

Polar bears ( Ursus maritimus Phipps, 1774) show fidelity to general denning areas in subsequent reproductive events. Studying the level and spatio-temporal scale of denning-area fidelity is critical to determine the adaptability of polar bears to climate change. We used mark–recapture data in conjunction with mitochondrial DNA (mtDNA) data to investigate the level of fidelity of polar bears from the Barents Sea population to five maternal denning areas. There was no differentiation in mtDNA haplotype frequencies between denning areas. The fidelity of females to denning areas is at a local geographic scale and small groups of neighboring females (3–13) shared similar haplotypes with higher probability than expected by chance. The transmission of denning-area fidelity is supported by the short distances (≤60.0 km) observed between capture locations of six (out of eight) denning mother–daughter pairs. Moreover, our results suggested that some females (3 out of 13) used different denning areas in subsequent denning events. This behavioral plasticity implies that females are likely to be able to change denning locations if unsuitable ice conditions prevent them from reaching their preferred denning areas. We consider this plasticity an important attribute of polar bears when facing climate change.

Prioritising prevention strategies for patients in antiretroviral treatment programmes in resource-limited settings

Expanded access to antiretroviral therapy (ART) offers opportunities to strengthen HIV prevention in resource-limited settings. We invited 27 ART programmes from urban settings in Africa, Asia and South America to participate in a survey, with the aim to examine what preventive services had been integrated in ART programmes. Twenty-two programmes participated; eight (36%) from South Africa, two from Brazil, two from Zambia and one each from Argentina, India, Thailand, Botswana, Ivory Coast, Malawi, Morocco, Uganda and Zimbabwe and one occupational programme of a brewery company included five countries (Nigeria, Republic of Congo, Democratic Republic of Congo, Rwanda and Burundi). Twenty-one sites (96%) provided health education and social support, and 18 (82%) provided HIV testing and counselling. All sites encouraged disclosure of HIV infection to spouses and partners, but only 11 (50%) had a protocol for partner notification. Twenty-one sites (96%) supplied male condoms, seven (32%) female condoms and 20 (91%) provided prophylactic ART for the prevention of mother-to child transmission. Seven sites (33%) regularly screened for sexually transmitted infections (STI). Twelve sites (55%) were involved in activities aimed at women or adolescents, and 10 sites (46%) in activities aimed at serodiscordant couples. Stigma and discrimination, gender roles and funding constraints were perceived as the main obstacles to effective prevention in ART programmes. We conclude that preventive services in ART programmes in lower income countries focus on health education and the provision of social support and male condoms. Strategies that might be equally or more important in this setting, including partner notification, prompt diagnosis and treatment of STI and reduction of stigma in the community, have not been implemented widely.

Ancestral polymorphism in exon 2 of bluethroat (Luscinia svecica) MHC class II B genes

The genes of the major histocompatibility complex (MHC) are important model genes for understanding selective forces in evolution. Here, we document, using a cloning and sequencing approach, high polymorphism at the exon 2 of the MHC class II B (MHCIIB) genes in the bluethroat (Luscinia svecica); a minimum of 61 unique alleles were detected in 20 individuals, and at least 11 functional loci. In addition, several pseudogenes were revealed. The specimens originated from three different bluethroat subspecies (azuricollis, cyanecula and svecica), and we also analysed four specimens of the closely related thrush nightingale (L. luscinia) for comparison. Phylogenetic analyses of the functional alleles revealed 258 equally parsimonious trees with poor statistical support for the majority of nodes. The distribution of the sequences in the trees point to an ancestral origin of the polymorphism in MHC class II B genes, a portion of which predated the phylogenetic split between the bluethroat and the thrush nightingale. Strong signatures of balancing selection were uncovered for the codons coding for the peptide-binding residues of the functional MHCIIB exon 2 alleles. Our results highlight the importance of duplication and recombination events for shaping passerine MHC and give insights in the evolutionary dynamics of MHC variation among closely related taxa.

The mating system of polar bears: a genetic approach

Parentage analysis data for 583 individuals genotyped at 27 microsatellite loci were used to study the mating system of polar bears ( Ursus maritimus Phipps, 1774) in the Barents Sea area. We discriminated statistically between full and half-siblings identified through only one common parent. We document for the first time multiple paternity in polar bears. We demonstrated for both sexes low fidelity to mating partners over time. We did not detect any significant difference between the age distribution of adult males at capture and the age distribution of males siring cubs. This might indicate that the male’s age and size are less indicative of the reproductive success than previously thought. This is further supported by a rather long mean litter interval of 3.9 years for males siring several litters. The mating system of polar bears in the Barents Sea appears to be promiscuous, usually with a single successful father siring full siblings within a year, but with consecutive litters of a mother being fathered by different males. We discuss how population density, landscape characteristics, and adult sex ratio might influence the mating system of polar bears. This is of particular importance for management decisions such as, e.g., implementing sex ratios in hunting quotas.

Influence of different oral rehydration solutions on abomasal conditions and the acid-base status of suckling calves

The aim of the study was to investigate the influence of oral rehydration solutions (ORS) on milk clotting, abomasal pH, electrolyte concentrations, and osmolality, as well as on the acid-base status in blood of suckling calves, as treatment with ORS is the most common therapy of diarrhea in calves to correct dehydration and metabolic acidosis. Oral rehydration solutions are suspected to inhibit abomasal clotting of milk; however, it is recommended to continue feeding cow's milk or milk replacer (MR) to diarrheic calves to prevent body weight losses. Three calves with abomasal cannulas were fed MR, MR-ORS mixtures, or water-ORS mixtures, respectively. Samples of abomasal fluid were taken before and after feeding at various time points, and pH, electrolyte concentrations, and osmolality were measured. The interference of ORS with milk clotting was examined in vivo and in vitro. To evaluate the effects of ORS on systemic acid-base status, the Stewart variables strong ion difference ([SID]), acid total ([A(tot)]), and partial pressure of CO2 (pCO2) were quantified in venous blood samples drawn before and after feeding. Calves reached higher abomasal pH values when fed with MR-ORS mixtures than when fed MR. Preprandial pH values were re-established after 4 to 6 h. Oral rehydration solutions prepared in water increased the abomasal fluid pH only for 1 to 2 h. Oral rehydration solutions with high [SID(3)] ([Na(+)] + [K(+)] - [Cl(-)]) values produced significantly higher abomasal pH values and area under the curve data of the pH time course. Caseinomacropeptide, an indicator of successful enzymatic milk clotting, could be identified in every sample of abomasal fluid after feeding MR-ORS mixtures. The MR-ORS mixtures with [SID(3)] values > or =92 mmol/L increased serum [SID(3)] but did not change venous blood pH. Oral rehydration solutions do not interfere with milk clotting in the abomasum and can, therefore, be administered with milk. In this study, MR-ORS mixtures with high [SID(3)] values caused an increase of serum [SID(3)] in healthy suckling calves and may be an effective treatment for metabolic acidosis in calves suffering from diarrhea.

Host-based identification is not supported by morphometrics in natural populations of Gyrodactylus salaris and G. thymalli (Platyhelminthes, Monogenea)

Gyrodactylus salaris is a serious pest of wild pre-smolt Atlantic salmon (Salmo salar) in Norway. The closely related G. thymalli, originally described from grayling (Thymallus thymallus), is assumed harmless to both grayling and salmon. The 2 species are difficult to distinguish using traditional, morphometric methods or molecular approaches. The aim of this study was to explore whether there is a consistent pattern of morphometrical variation between G. salaris and G. thymalli and to analyse the morphometric variation in the context of ‘diagnostic realism’ (in natural populations). Specimens from the type-material for the 2 species are also included. In total, 27 point-to-point measurements from the opisthaptoral hard parts were used and analysed by digital image processing and uni- and multivariate morphometry. All populations most closely resembled its respective type material, as expected from host species, with the exception of G. thymalli from the Norwegian river Trysilelva. We, therefore, did not find clear support in the morphometrical variation among G. salaris and G. thymalli for an a priori species delineation based on host. The present study also indicates an urgent need for more detailed knowledge on the influence of environmental factors on the phenotype of gyrodactylid populations.

Genetic variation in Holocene bowhead whales from Svalbard

Bowhead whales (Balaena mysticetus) are distributed in the Arctic in five putative stocks. All stocks have been heavily depleted due to centuries of exploitation. In the present study, nucleotide sequence variation of the mitochondrial control region was determined from bone remains of 99 bowhead whales. The bones, 14C dated from recent to more than 50,000 bp, were collected on Svalbard (Spitsbergen) and are expected to relate to ancestors of the today nearly extinct Spitsbergen stock. Fifty-eight haplotypes were found, a few being frequent but many only found in one individual. The most abundant haplotypes of the Spitsbergen stock are the same as those most abundant in the extant Bering-Chukchi-Beaufort (BCB) Seas stock of bowhead whales. Although F(ST) indicates a slight but statistically significant genetic differentiation between the Spitsbergen and the BCB stocks this was not considered informative due to the very high levels of genetic diversity of mitochondrial DNA haplotypes in both bowhead whale stocks. Other measures such as K(ST) also indicated very low genetic differentiation between the two populations. Nucleotide diversity and haplotype diversity showed only minor differences between the Spitsbergen and BCB stocks. The data suggest that the historic Spitsbergen stock--before the severe bottleneck caused by whaling--did not have substantially more genetic variation than the extant BCB stock. The similar haplotypes of the Holocene Svalbard samples and the current BCB stock indicate significant migration between these two stocks and question the current designation of five distinct stocks of bowhead whales in the Arctic.

Variation in host preference within Gyrodactylus salaris (Monogenea): an experimental approach

The monogenean ectoparasite, Gyrodactylus salaris Malmberg, 1957, has had a devastating effect on wild Atlantic salmon (Salmo salar) since its introduction to Norway in the mid-1970s. In Lake Pålsbufjorden, southern Norway, upstream of the stretches of the River Numedalslågen with anadromous Atlantic salmon, a resident Arctic charr (Salvelinus alpinus) population has been reported to be infected with G. salaris which is viable in the absence of its normal host, the Atlantic salmon. Currently, there is no record of G. salaris infecting Atlantic salmon in the downstream sections of the River Numedalslågen. We studied experimentally the infectivity and reproductive capacity of G. salaris from Lake Pålsbufjorden on wild and hatchery-reared Atlantic salmon as well as on Arctic charr and rainbow trout (Oncorhynchus mykiss). Arctic charr and rainbow trout were moderately susceptible, whereas the Atlantic salmon stocks from River Numedalslågen and River Drammenselva were innately resistant to only slightly susceptible. Thus, the G. salaris from Arctic charr in Lake Pålsbufjorden is considered non-pathogenic to Atlantic salmon. This is the first observation of variation in host preference among Norwegian G. salaris populations. The observed differences in virulence between G. salaris populations could have important consequences for the international legislation and management of Atlantic salmon.

The mitochondrial genome of Gyrodactylus salaris (Platyhelminthes: Monogenea), a pathogen of Atlantic salmon (Salmo salar)

In the present study, we describe the complete mitochondrial (mt) genome of the Atlantic salmon parasite Gyrodactylus salaris, the first for any monogenean species. The circular genome is 14 790 bp in size. All of the 35 genes recognized from other flatworm mitochondrial genomes were identified, and they are transcribed from the same strand. The protein-coding and ribosomal RNA (rRNA) genes share the same gene arrangement as those published previously for neodermatan mt genomes (representing cestodes and digeneans only), and the genome has an overall A+T content of 65%. Three transfer RNA (tRNA) genes overlap with other genes, whereas the secondary structure of 3 tRNA genes lack the DHU arm and 1 tRNA gene lacks the TΨC arm. Eighteen regions of non-coding DNA ranging from 4 to 112 bp in length, totalling 278 bp, were identified as well as 2 large non-coding regions (799 bp and 768 bp) that were almost identical to each other. The completion of the mt genome offers the opportunity of defining new molecular markers for studying evolutionary relationships within and among gyrodactylid species.

Arctic charr (Salvelinus alpinus) is a suitable host for Gyrodactylus salaris (Monogenea, Gyrodactylidae) in Norway

Gyrodactylus specimens infecting both anadromous Arctic charr (Salvelinus alpinus) from River Signaldalselva (northern Norway) and resident Arctic charr from Lake Pålsbufjorden (southern Norway) were identified as G. salaris using molecular markers and morphometrics. The infection in Pålsbufjorden represents the first record of a viable G. salaris population infecting a host in the wild in the absence of salmon (Salmo salar). G. salaris on charr from Signaldalselva and Pålsbufjorden bear different mitochondrial haplotypes. While parasites infecting charr in Signaldalselva carry the same mitochondrial haplotype as parasites from sympatric Atlantic salmon, G. salaris from charr in Pålsbufjorden bear a haplotype that has previously been found in parasites infecting rainbow trout (Oncorhynchus mykiss) and Atlantic salmon, and an IGS repeat arrangement that is very similar to those observed earlier in parasites infecting rainbow trout. Accordingly, the infection may result from 2 subsequent host-switches (from salmon via rainbow trout to charr). Morphometric analyses revealed significant differences between G. salaris infecting charr in the 2 localities, and between those on sympatric charr and salmon within Signaldalselva. These differences may reflect adaptations to a new host species, different environmental conditions, and/or inherited differences between the G. salaris strains. The discovery of G. salaris on populations of both anadromous and resident charr may have severe implications for Atlantic salmon stock-management as charr may represent a reservoir for infection of salmon.

The incongruence of nuclear and mitochondrial DNA variation supports conspecificity of the monogenean parasites Gyrodactylus salaris and G. thymalli

The monogenean Gyrodactylus salaris Malmberg, 1957 is an economically important parasite on Atlantic salmon whereas the morphologically very similar G. thymalli Zitnan, 1960 on grayling is considered harmless. Even molecular markers cannot unambiguously discriminate both species. The nuclear internal transcribed spacer (ITS) sequences are identical in both species, and although mitochondrial cytochrome oxidase I (COI) sequences show substantial variation, no support for monophyly of either species is found. Analysis of nucleotide sequences of the intergenic spacer (IGS) have, however, been interpreted as support for 2 species. Here, IGS and COI sequences from 81 G. salaris and G. thymalli specimens of 39 populations across the species' distribution range were determined. Mitochondrial diversity was not reflected in the nuclear marker. Since various 23 bp IGS repeat types usually differ by just one nucleotide and sequences primarily differ in the number and order of repeat types, alignments may be biased and arbitrary, impeding meaningful phylogenetic analyses. The hypothesis that parasites on rainbow trout represent hybrids of both species is rejected. The presence or absence of particular repeat types is not considered informative. We interpret the IGS data as support for G. salaris and G. thymalli being a single species.

PCR-Induced Sequence Alterations Hamper the Typing of Prehistoric Bone Samples for Diagnostic Achondroplasia Mutations

Achondroplasia (ACH) is a skeletal disorder (MIM100800) with an autosomal dominant Mendelian inheritance and complete penetrance. Here we report the screening of ancient bone samples for diagnostic ACH mutations. The diagnostic G-->A transition in the FGFR3 gene at cDNA position 1138 was detected in cloned polymerase chain reaction (PCR) products obtained from the dry mummy of the Semerchet tomb, Egypt (first dynasty, approximately 4,890-5,050 BP [before present]), and from an individual from Kirchheim, Germany (Merovingian period, approximately 1,300-1,500 BP), both of which had short stature. However, these mutations were also reproducibly observed in four ancient control samples from phenotypically healthy individuals (false-positives), rendering the reliable molecular typing of ancient bones for ACH impossible. The treatment of a false-positive DNA extract with uracil N-glycosylase (UNG) to minimize type 2 transitions (G-->A/C-->T) did not reduce the frequency of the false-positive diagnostic ACH mutations. Recently, it was suggested that ancient DNA extracts may induce mutations under PCR. Contemporary human template DNA from a phenotypically healthy individual was therefore spiked with an ancient DNA extract from a cave bear. Again, sequences with the diagnostic G-->A transition in the FGFR3 gene were observed, and it is likely that the false-positive G-->A transitions result from errors introduced during the PCR reaction. Amplifications in the presence of MnCl(2) indicate that position 1138 of the FGFR3 gene is particularly sensitive for mutations. Our data are in line with previously published results on the occurrence of nonrandom mutations in PCR products of contemporary human mitochondrial HVRI template DNA spiked with ancient DNA extracts.

[Manipulation of blood pressure self-monitoring protocol values: a randomized controlled study]

Treatment monitoring of hypertensive patients can be achieved using data from blood pressure measurements obtained in follow-up visits, from sporadic 24 hours ambulatory blood pressure monitoring (ABPM) and from patients' self-measurements. Blood pressure self-measurement values seem to be the easiest to obtain. A disadvantage is the uncertainty about the accuracy with which patients report these values. In this randomised clinical trial with 48 hypertensive outpatients we compared reported self-measurements with the stored values in the devices. One group was unaware of the storing capacity of the device. All patients measured their blood pressure twice in the morning and twice in the evening over a period of 14 days. Endpoints of our analysis were the comparison of the number of measurements performed and the missing and manipulated values between the two groups. The non-informed group measured blood-pressure more frequently than the informed group (76.1 vs. 58.8 measurements; p = 0.0005). Compared to the informed group, the number of agreements between stored and reported values was smaller in the non-informed group (95.7% vs. 87.5%; p = 0.026) whereas reporting of fictional data only occurred in the non-informed group (0 vs. 55; p = 0.002). Our data show, that use of blood-pressure devices with a memory function increases the accuracy of reported self-measured values and can lead to better treatment monitoring.

Evolutionary dynamics of the SGM transposon family in the Drosophila obscura species group

SGM (Drosophila subobscura, Drosophila guanche, and Drosophila madeirensis) transposons are a family of transposable elements (TEs) in Drosophila with some functional and structural similarities to miniature inverted-repeat transposable elements (MITEs). These elements were recently active in D. subobscura and D. madeirensis (1-2 MYA), but in D. guanche (3-4 MYA), they gave rise to a species-specifically amplified satellite DNA making up approximately 10% of its genome. SGM elements were already active in the common ancestor of all three species, giving rise to the A-type specific promoter section of the P:-related neogene cluster. SGM sequences are similar to elements found in other obscura group species, such as the ISY elements in D. miranda and the ISamb elements in Drosophila ambigua. SGM elements are composed of different sequence modules, and some of them, i.e., LS and LS-core, are found throughout the Drosophila and Sophophora radiation with similarity to more distantly related TEs. The LS-core module is highly enriched in the noncoding sections of the Drosophila melanogaster genome, suggesting potential regulatory host gene functions. The SGM elements can be considered as a model system elucidating the evolutionary dynamics of mobile elements in their arms race with host-directed silencing mechanisms and their evolutionary impact on the structure and composition of their respective host genomes.

Hammerhead-mediated processing of satellite pDo500 family transcripts from Dolichopoda cave crickets

This work reports the discovery and functional characterization of catalytically active hammerhead motifs within satellite DNA of the pDo500 family from several DOLICHOPODA: cave cricket species. We show that in vitro transcribed RNA of some members of this satellite DNA family do self-cleave in vitro. This self-cleavage activity is correlated with the efficient in vivo processing of long primary transcripts into monomer-sized RNA. The high sequence conservation of the satellite pDo500 DNA family among genetically isolated DOLICHOPODA: schiavazzii populations, as well as other DOLICHOPODA: species, along with the fact that satellite members are actively transcribed in vivo suggests that the hammerhead-encoding satellite transcripts are under selective pressure, perhaps because they fulfil an important physiological role or function. Remarkably, this is the third example of hammerhead ribozyme structures associated with transcribed repetitive DNA sequences from animals. The possibility that such an association may not be purely coincidental is discussed.