Trans- and paracellular calcium transport along the small and large intestine in horses.

Intestinal calcium absorption plays a key role in the maintenance of calcium homeostasis and may either occur by paracellular or transcellular mechanisms. The horse has some unique peculiarities in calcium homeostasis compared to other species including a high absorptive capacity for calcium in the intestine, high plasma calcium concentrations, high renal excretion, and low plasma concentrations of vitamin D metabolites. So far, knowledge about the underlying mechanisms and the regulation of intestinal calcium absorption is still limited concerning this species. Several studies have documented that intestinal calcium transport in horses is not as dependent on vitamin D as in other species. However, published data on other potential regulatory mechanisms are still lacking. In the present study, paracellular and transcellular transport mechanisms for intestinal calcium transport along the intestinal axis were identified in horses using the Ussing chamber technique. Furthermore, the expression of respective transport proteins including transient receptor potential vanilloid member 6, calbindin-D9k and calcium ATPase type 1 in line with the determined calcium flux rates was documented. In respect to regulation of transepithelial calcium transport, novel regulatory proteins for maintaining calcium homeostasis such as B-box and SPRY-domain containing protein and calmodulin were investigated for the first time in equine intestinal tissues in this study. This provides the basis for a new approach for a better understanding of equine calcium homeostasis regulation.

Stimulating effects of a diet negative in dietary cation-anion difference on calcium absorption from the rumen in sheep.

The concept of feeding anionic salts in late gestation is widely used to prevent milk fever in dairy cows. While the effects of these diets on renal Ca excretion and tissue responsiveness towards parathyroid hormone have clearly been demonstrated, data on a potential impact on gastrointestinal Ca absorption are conflicting. Therefore, the aim of this study was to investigate the influence of feeding a diet negative in dietary cation-anion difference (DCAD) on ruminal mineral concentrations, fermentation products, electrophysiological properties of rumen epithelia and Ca flux rates. For this purpose, sheep were kept for 3 weeks on diets that were either positive or negative in DCAD. The induction of a compensated hyperchloremic metabolic acidosis could be demonstrated by increased plasma Cl and enhanced concentrations of ionised Ca, while plasma concentrations of HCO3- and base excess were decreased with the low DCAD diet. Neither transmural potential differences nor fermentation products were affected, but ruminal concentrations of Cl and Mg as well as the relation of ionised to total Ca were increased. Ussing chamber experiments revealed alterations of electrophysiological parameters and an increase in the electroneutral component of Ca flux rates from the mucosal to the serosal side of rumen epithelium. As plasma calcitriol concentrations were not affected, it can be concluded that the administration of anionic salts results in a vitamin D-independent stimulation of ruminal Ca transport.

Measurement of Compton scattering from the deuteron and an improved extraction of the neutron electromagnetic polarizabilities.

The electromagnetic polarizabilities of the nucleon are fundamental properties that describe its response to external electric and magnetic fields. They can be extracted from Compton-scattering data-and have been, with good accuracy, in the case of the proton. In contradistinction, information for the neutron requires the use of Compton scattering from nuclear targets. Here, we report a new measurement of elastic photon scattering from deuterium using quasimonoenergetic tagged photons at the MAX IV Laboratory in Lund, Sweden. These first new data in more than a decade effectively double the world data set. Their energy range overlaps with previous experiments and extends it by 20 MeV to higher energies. An analysis using chiral effective field theory with dynamical Δ(1232) degrees of freedom shows the data are consistent with and within the world data set. After demonstrating that the fit is consistent with the Baldin sum rule, extracting values for the isoscalar nucleon polarizabilities, and combining them with a recent result for the proton, we obtain the neutron polarizabilities as αn=[11.55±1.25(stat)±0.2(BSR)±0.8(th)]×10(-4) fm(3) and ßn=[3.65∓1.25(stat)±0.2(BSR)∓0.8(th)]×10(-4) fm(3), with χ(2)=45.2 for 44 degrees of freedom.

P-glycoprotein in sheep liver and small intestine: gene expression and transport efflux activity.

The role of the transporter P-glycoprotein (P-gp) in the disposition kinetics of different drugs therapeutically used in veterinary medicine has been demonstrated. Considering the anatomo-physiological features of the ruminant species, the constitutive expression of P-gp (ABCB1) along the sheep gastrointestinal tract was studied. Additionally, the effect of repeated dexamethasone (DEX) administrations on the ABCB1 gene expression in the liver and small intestine was also assessed. The ABCB1 mRNA expression was determined by real-time quantitative PCR. P-gp activity was evaluated in diffusion chambers to determine the efflux of rhodamine 123 (Rho 123) in the ileum from experimental sheep. The constitutive ABCB1 expression was 65-fold higher in the liver than in the intestine (ileum). The highest ABCB1 mRNA expression along the small intestine was observed in the ileum (between 6- and 120-fold higher). The treatment with DEX did not elicit a significant effect on the P-gp gene expression levels in any of the investigated gastrointestinal tissues. Consistently, no significant differences were observed in the intestinal secretion of Rho 123, between untreated control (Peff S-M = 3.99 × 10(-6)  ± 2.07 × 10(-6) ) and DEX-treated animals (Peff S-M = 6.00 × 10(-6)  ± 2.5 × 10(-6) ). The understanding of the efflux transporters expression and activity along the digestive tract may help to elucidate clinical implications emerging from drug interactions in livestock.

Influence of the combination of 25-hydroxyvitamin D3 and a diet negative in cation-anion difference on peripartal calcium homeostasis of dairy cows.

Around parturition, many dairy cows experience varying degrees of hypocalcemia, which increases the incidence of several diseases in early lactation. In the current study, an established concept of feeding a diet negative in cation-anion difference (DCAD) was combined with oral supplementation of 25-hydroxyvitamin D(3) (25-OHD(3)) from d 270 of gestation until parturition. Fifty-six dairy cows were divided into 2 feeding groups (low DCAD and control). Fourteen animals of each group received a daily dosage of 3mg of 25-OHD(3). From the beginning of the treatment to d 10 after parturition, plasma samples for analysis of 25-OHD(3), 1,25-dihydroxyvitamin D(3), parathyroid hormone (PTH), Ca(2+), phosphate, the bone resorption marker CrossLaps, and osteocalcin were collected every other day, at calving, and at 6, 12, and 24h after calving. Urine samples for determination of macrominerals and measures of acid-base status were collected on d 6 of treatment and on d 6 after calving. The induction of a compensated metabolic acidosis by the animals on the DCAD diet could be demonstrated by decreased urinary pH. A linear correlation between treatment duration and the plasma concentration of 25-OHD(3) indicated effective absorption of 25-OHD(3) in supplemented animals. The mean plasma concentrations of Ca(2+) from d -4 prepartum to d 4 postpartum were significantly higher in animals treated with the combination of the low DCAD diet and 25-OHD(3) supplementation (1.24±0.02 mmol/mL) compared with the 3 other groups (low DCAD: 1.17±0.02 mmol/mL; control diet plus 25-OHD(3): 1.16±0.02 mmol/mL; control diet: 1.18±0.02 mmol/mL). We postulate that the increased tissue responsiveness to parathyroid hormone induced by the low DCAD is crucial for the observed positive effects of the 25-OHD(3) treatment.

Cytochrome P450 3A expression and function in liver and intestinal mucosa from dexamethasone-treated sheep.

The effects of repeated administrations of dexamethasone (DEX) (3 mg/kg/day by i.m. route for 7 days) on the gene expression profile of a cytochrome P450 (CYP) 3A28-like isoenzyme, on the expression of a CYP3A-immunoreactive protein and on CYP3A-dependent metabolic activities in sheep liver and small intestinal mucosa were evaluated in the current work. CYP 3A-dependent metabolic activities (erythromycin and triacetyl-oleandomycin N-demethylations) were assessed in microsomal fractions. The mRNA expression of CYP3A28-like, glucocorticoid receptor, constitutive androstane receptor, pregnane X receptor and retinoic X receptor alpha (RXRα) was determined by quantitative real-time PCR. The expression of a CYP3A-immunoreactive protein was measured by Western blot analyses. In the liver, DEX treatment increased CYP3A28-like mRNA levels (2.67-fold, P<0.01) and CYP3A apoprotein expression (1.34-fold, P<0.05) and stimulated CYP3A-dependent metabolism. High and significant correlation coefficients between CYP3A-dependent activities and CYP3A28-like gene (r=0.835-0.856, P<0.01) or protein (r=0.728-0.855, P<0.05) expression profiles were observed. Among the transcriptional factors, DEX only stimulated (2.1-fold, P<0.01) the mRNA expression of RXRα. In sheep small intestine, DEX caused a slight increment (34.6%, P<0.05) in erythromycin N-demethylase activity in the jejunal mucosa and a significant enhancement (P<0.05) of CYP3A apoprotein level in the duodenal mucosa.

Multimodal Assessment of Smoking cue Reactivity During a Smoking Cue Exposure Task.

Background. Cue-reactivity as a characteristic symptom of substance use disorders (SUD) is highly context dependent. Paradigms with high context validity need to be established for the investigation of underlying neurobiological mechanisms. While craving can be assessed by self-report as one aspect of cue-reactivity (CR), the assessment of biological measures such as the autonomous response and EEG promises a holistic perspective including CR at an automatized level. In a multimodal approach, smoking cue exposure (CE) effects on heart rate variability (HRV), EEG frequency power, and craving as well as their interrelation were assessed. This pilot study focused on the validity of CR measurements in a naturalistic CE paradigm. Methods. EEG frequency power, HRV, and craving were assessed during resting state (RS) and smoking CE in smokers (n = 14) and nonsmoking controls (n = 10) to investigate the psychophysiological and subjective reactions to CE. Results. Increased beta power was found only in smokers during CE compared to the control condition. There was an inverse correlation of beta power and maximum craving. Likewise, HRV correlated negatively with maximum smoking urges in smokers immediately after the measurements, without differentiation between CE and control condition. Conclusion. The increased beta power in smokers during CE is discussed as increased inhibitory control related to reduced craving in smokers. Furthermore, increased craving during CE seems to be associated to decreased vagal activity. The multimodal measurements during the CE showed ecological validity to be fundamental for CE assessment in clinical populations to evaluate its predictive value.

Short communication: transport of 2-hydroxy-4-methyl-thio-butanoic isopropyl ester by rumen epithelium in vitro.

Our objective was to evaluate the potential of rumen epithelium to transport 2-hydroxy-4-(methylthio)-butanoic isopropyl ester (HMBi) using the Ussing chamber technique. Rumen tissues were obtained from a nearby slaughterhouse, separated from the muscle and serosal layer as quickly as possible after exsanguination, placed in buffer, and gassed with 95:5 (vol/vol) O(2):CO(2) before tissue mounting. Two levels of HMBi (0.44 and 0.88 mg/mL) and 2 incubation times (120 and 180 min) were used in 12 chambers with 3 replicates per treatment with an exposed surface area of 2 cm(2). Four separate experiments were conducted (n=16). Concentrations of HMBi and methionine hydroxy analog (HMB) were measured by HPLC in rumen-side and serosal-side buffers. Data are expressed as percentage of added HMBi. Initial time samples were taken for comparison with incubated samples. Adding the HMBi-buffer mixture to the rumen side caused an immediate release of HMB (mean=6.3%). Breakdown of HMBi to HMB at initial time was due to hydrolysis reactions at the epithelial surface. Overall, a small and variable amount of HMBi was transferred to the serosal buffer (mean of 0.58% across both times and both concentrations). A larger amount of HMB (8.94%) was isolated in the serosal buffer. Increasing incubation time increased the amount of HMB in the ruminal buffer (34.0% at 120 min vs. 43.4% at 180 min) and decreased the amount of HMBi (37.9% at 120 min vs. 28.1% at 180 min). These data indicate that very limited amounts of HMBi may cross the rumen epithelium. The amount of HMB isolated on the serosal side was about 10 times higher than HMBi. The hydrolysis of HMBi to HMB required the presence of rumen tissue or perhaps microbes attached to the tissue. Based on this in vitro system, direct transport from the rumen would not explain rapid blood methionine increases observed when HMBi is fed.

Intracellular trafficking of lysosomal proteins and lysosomes.

In the synthesis and trafficking of precursors of most lysosomal matrix proteins, the stages necessary for lysosomal delivery include the addition of phosphorylated mannose-rich oligosaccharides, binding of the modified proteins to receptors, their segregation from the secretory pathways and delivery to the endosomal pathway. Targeting of both internally synthesized and externally provided enzymes (as in enzyme replacement therapy) to endosomes is executed by a complex machinery of membrane and cytosolic proteins. Recently, the homotypic fusion and vacuolar protein sorting (HOPS) complex has been identified in lysosomes from human cells. This complex is likely to play an important role in the exchange of enzymes between endosomal and lysosomal compartments. The present review describes the interactions and functions of proteins that participate in delivering lysosomal proteins to different lysosomal compartments. In summary, lysosomal trafficking depends on the recognition of many structural signals. It delivers soluble and membrane proteins, and can be exploited for therapeutic substitution of missing enzymes.

[Mission and tasks of the Coordination Centres for Clinical Trials]. / Aufgaben der Koordinierungszentren für Klinische Studien.

Coordination Centres for Clinical Trials (Koordinierungszentren für Klinische Studien, KKS) were set up to increase the quality and number of clinical trials in Germany as well as to establish clinical trial training programs in order to improve international recognition of German clinical research. Over the past 6 years, 12 KKS have been set up at the respective universities with a public grant from the Federal Ministry of Education and Research (BMBF). Many non-clinical services have been established to ensure successful co-operation in clinical trials with clinical scientists and industry. KKS help researchers to efficiently conduct commercial and non-commercial clinical trials in various disease areas. Their expertise and infrastructure allow the university to assume sponsor responsibility in non-commercial drug trials. Because of their professional work and education activities KKS are well accepted by industry and the scientific community. Central professional trial organisations such as the KKS have been shown to be the pre-requisite for meeting the growing, manifold and complex requirements for clinical trials. Therefore they are considered essential for progress and success in clinical research.

Rabies outbreak in African Wild Dogs (Lycaon pictus) in the Tuli region, Botswana: Interventions and management mitigation recommendations.

We describe an outbreak of rabies in a pack of African wild dogs (Lycaon pictus) in the Limpopo-Lipadi Private Game and Wilderness Reserve in the Tuli region of south-eastern Botswana. We define the pack's behavioural response to the disease, clinical signs, and management interventions undertaken and make recommendations to mitigate against future disease outbreaks of this nature. The outbreak, which occurred in late 2014 and early 2015, resulted in the death or disappearance of 29 individuals out of a pack of 35 wild dogs. The disruption to the social structure within the pack, the behaviour of the animals and clinical signs were similar to that documented during previous rabies outbreaks amongst African wild dogs in Southern and East Africa in recent years. Management interventions taken during the outbreak were aimed at preventing extirpation of the pack and reducing the risk of further disease spread to other mammals in the reserve.

Chloride, gluconate, sulfate, and short-chain fatty acids affect calcium flux rates across the sheep forestomach epithelium.

In ruminants, more than 50% of overall gastrointestinal Ca absorption can occur preintestinally, and the anions of orally applied Ca salts are thought to play an important role in stimulating ruminal Ca absorption. This assumption is based mainly on ion-exchange studies that have used gluconate as the control anion, which may bind Ca2+ ions and interfere with treatment effects. In the present study, we investigated the distinct effects of different anions on Ca absorption across the sheep rumen and on the concentration of free Ca2+ ions ([Ca2+]ion). We showed that gluconate, sulfate, and short-chain fatty acids (SCFA) remarkably reduced [Ca2+]ion in buffer solutions. Nevertheless, increasing the Cl or SCFA concentration by 60 mM stimulated net ruminal Ca absorption 5- to 7-fold, but these effects could be antagonized by gluconate. Therefore, ion-exchange experiments must be (re)evaluated very carefully, because changes in [Ca2+]ion in the presence of gluconate, sulfate, or SCFA not only might entail an underestimation of Ca flux rates, but also might have effects on other cellular pathways that are Ca2+ dependent. Concerning the optimal Ca supply for dairy cows, the present study suggests that CaCl2 formulations and Ca salts of the SCFA stimulate Ca absorption across the rumen wall and are beneficial in preventing or correcting a Ca deficiency.

Segmental diversity of phosphate transport along the intestinal axis in horses.

For horses, distinct differences in intestinal phosphate transport have been postulated to account for the unique features of hind gut fermentation compared to other monogastric animals and ruminants. So far published data on mechanisms and underlying transport proteins involved in intestinal phosphate transport in the horse are still missing. Therefore we investigated intestinal phosphate transport in horses at both functional and molecular levels. Segmental diversity of intestinal phosphate transport along the intestinal axis was documented using the Ussing chamber technique. A transcellular phosphate secretion in the jejunum was confirmed. Furthermore, 2 sodium-dependent phosphate cotransporters, NaPiIIb and PiT1, were first detected in the equine intestine at mRNA level with PiT1 being expressed in both the small and large intestine, and NaPiIIb being solely expressed in the large intestine. In the colon, unidirectional net flux rates of phosphate were significantly greater compared to flux rates in other segments ( < 0.005) suggesting the colon as a major site for phosphate absorption in horses. Phosphate transport in the colon was mainly transcellular and mediated by a sodium-gradient as documented by Ussing chamber experiments and uptake of phosphate into colonic brush border membrane vesicles. In summary, the present study demonstrated mechanisms and transporters of intestinal phosphate transport in equine intestinal tissues with distinct differences between intestinal segments providing a new basis for a better understanding of intestinal phosphate transport in horses.

A survey of free-living ixodid ticks on a commercial game farm in the Thabazimbi District, Limpopo Province, South Africa.

Free-living stages of ticks on a commercial game farm in the Thabazimbi District, Limpopo Province, South Africa, were collected by drag-sampling with flannel strips during the period September 2003 to August 2004. A total of 5 tick species was collected from 4 sites. Boophilus decoloratus was the most abundant species, followed by Amblyomma hebraeum. Seasonal abundance of the ticks was quantified and an optimum time to implement control measures against the ticks is proposed.

The effects of 1,25-dihydroxyvitamin D-3 deficiency on Ca(2+)-transport and Ca(2+)-uptake into brush-border membrane vesicles from pig small intestine.

BBMV were prepared from duodenal segments of untreated, 1,25-(OH)2D3- or vitamin D-3-treated rachitic piglets and from non-rachitic controls by the Mg2+ precipitation method. The rachitic piglets were offspring from the 'Hannover Pig Strain' which suffer from pseudo vitamin D-deficiency rickets, type I (no renal 1-hydroxylase activity). Initial uptake of Ca2+ (up to 35 s) at low [Ca2+] (between 0.02-0.25 mmol/l) into isolated BBMV consisted of a saturable and non-saturable component. The apparent Vmax of the saturable component was significantly lower in rachitic piglets than in control piglets. In the presence of an inside negative potassium diffusion potential, the difference in uptake extended over at least 15 min. The apparent Km of Ca(2+)-uptake was not influenced by the rachitic condition. Treatment of rachitic piglets with sequential doses of 1,25-(OH)2D3 for three days (1 microgram/day) or with a single dose (2.5 mg) of vitamin D-3 elevated the saturable Ca(2+)-uptake component to values similar to those of control piglets. Addition of 1 mmol/l verapamil to the vesicular suspension inhibited Ca(2+)-uptake in BBMV of control piglets by 40-60% but was without effect on preparations from rachitic piglets. It was concluded from the study that 1,25-(OH)2D3 dependent Ca(2+)-uptake into BBMV constituted a saturable process which can be inhibited by a known Ca(2+)-channel blocking agent. It appears that 1,25-(OH)2D3 increases the number of verapamil sensitive Ca(2+)-transport components in brush-border membranes. The vitamin D-dependent changes in vesicular Ca(2+)-uptake were paralleled by the expression of an active transmural Ca(2+)-transport across the mucosa.

Rho family small GTPases control migration of hematopoietic progenitor cells into multicellular spheroids of bone marrow stroma cells.

Seeding of hematopoietic progenitor cells (HPC) into the bone marrow requires a complex interaction between cell membrane and adhesion systems and cell signaling pathways. We established a multicellular, spheroid coculture model to study HPC migration in a three-dimensional stromal environment. Here, entry of primary CD34(+) cells into stroma cell spheroids was independent of the integrins very late antigen (VLA)-4, VLA-5, lymphocyte function-associated antigen-1, and the chemokine receptor CXCR4. Experiments using a panel of bacterial toxins selectively targeting key regulators of cellular locomotion, the Rho family small GTPases Rho, Rac, and Cdc42, revealed a considerable reduction or even abrogation of TF-1 cell migration without an increase of apoptosis or impairment of proliferation. Pertussis toxin, an inhibitor of Galpha(i) proteins, showed a similar effect. In some in vitro invasion assays, phosphatidylinositol-3 kinase (PI-3K) was shown to mediate Rac- and Cdc42-induced cell motility and invasion. However, inhibition of the PI-3K pathway by LY294002 did not impair TF-1 cell migration in our three-dimensional model system.

Towards a commercial process for the manufacture of genetically modified T cells for therapy.

The recent successes of adoptive T-cell immunotherapy for the treatment of hematologic malignancies have highlighted the need for manufacturing processes that are robust and scalable for product commercialization. Here we review some of the more outstanding issues surrounding commercial scale manufacturing of personalized-adoptive T-cell medicinal products. These include closed system operations, improving process robustness and simplifying work flows, reducing labor intensity by implementing process automation, scalability and cost, as well as appropriate testing and tracking of products, all while maintaining strict adherence to Current Good Manufacturing Practices and regulatory guidelines. A decentralized manufacturing model is proposed, where in the future patients' cells could be processed at the point-of-care in the hospital.

Renal mechanisms of calcium homeostasis in sheep and goats.

In small ruminants, the renal excretion of calcium (Ca) and phosphate (Pi) is not modulated in response to dietary Ca restriction. Although this lack of adaptation was observed in both sheep and goats, differences in renal function between these species cannot be excluded. Recent studies demonstrated that compared with sheep, goats have a greater ability to compensate for challenges to Ca homeostasis, probably due to a more pronounced increase in calcitriol production. Therefore, the aim of the present study was to examine the effect of 1) dietary Ca restriction, 2) administration of calcitriol, and 3) lactation on Ca and Pi transport mechanisms and receptors as well as enzymes involved in vitamin D metabolism in renal tissues of sheep and goats. Whereas RNA expression of renal transient receptor potential vanilloid channel type 5 was unaffected by changes in dietary Ca content, a significant stimulation was observed with administration of calcitriol in both sheep (P < 0.001) and goats (P < 0.01). Calbindin-D28K was downregulated during dietary Ca restriction in goats (P < 0.05). Expression of the sodium/Ca exchanger type 1 was decreased by low Ca intake in sheep (P < 0.05) and upregulated by calcitriol treatment in goats (P < 0.05). A significant reduction in RNA expression of the cytosolic and the basolateral Ca transporting proteins was also demonstrated for lactating goats in comparison to dried-off animals. Species differences were found for vitamin D receptor expression, which was stimulated by calcitriol treatment in sheep (P < 0.01) but not in goats. As expected, expression of 1α-hydroxylase was upregulated by dietary Ca restriction (P < 0.001; P < 0.05) and inhibited by exogenous calcitriol (P < 001; P < 0.05) in both sheep and goats. However, whereas 24-hydroxylase expression was stimulated to the same extent by calcitriol treatment in sheep, irrespective of the diet (P < 0.001), a modulatory effect of dietary Ca supply on 24-hydroxylase induction was observed in goats (P < 0.05). Taken together, our results confirm observations that modulation of renal Ca excretion does not contribute to maintenance of Ca homeostasis in these ruminants during restricted dietary supply, unlike responses in monogastric animals. The interesting species differences related to vitamin D metabolism might explain the greater capacity of goats to compensate for challenges of Ca homeostasis and should be further investigated.