| 1. |
- Vicente Carrillo, Alejandro, 1989-
(författare)
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Sperm Membrane Channels, Receptors and Kinematics : Using boar spermatozoa for drug toxicity screening
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internal fertilization usually implies that a spermatozoon, with intact attributes for zygote formation, passes all hurdles during its transport through the female genitalia and reaches the oocyte. During this journey, millions to billions of other spermatozoa perish. Spermatozoa are highly differentiated motile cells without synthetic capabilities. They generate energy via glycolysis and oxidative phosphorylation to sustain motility and to maintain the stability and functionality of their plasma membrane. In vivo, they spend their short lifespan bathing in female genital tract fluids of different origins, or are in vitro exposed to defined media during diverse sperm handling i.e. extension, cryopreservation, in vitro fertilization, etc. Being excitable cells, spermatozoa respond in vivo to various stimuli during pre-fertilization (capacitation, hyperactivation, oocyte location) and fertilization (acrosome reaction, interaction with the oocyte) events, mediated via diverse membrane ion-conducting channels and ligand-gated receptors. The present Thesis has mapped the presence and reactivity (sperm intactness and kinematics) of selected receptors, water and ion channels in ejaculated boar spermatozoa. The final aim was to find a relevant alternative cell type for in vitro bioassays that could ease the early scrutiny of candidate drugs as well as decreasing our needs for experimental animals according to the 3R principles. Spermatozoa are often extended, cooled and thawed to warrant their availability as fertile gametes for breeding or in vitro testing. Such manipulations stress the cells via osmotic variations and hence spermatozoa need to maintain membrane intactness by controlling the exchange of water and the common cryoprotectant glycerol, via aquaporins (AQPs). Both AQPs-7 and -9 were studied for membrane domain changes in cauda- and ejaculated spermatozoa (un-processed, extended, chilled or frozen-thawed). While AQP-9 maintained location through source and handling, thawing of ejaculated spermatozoa clearly relocated the labelling of AQP-7, thus appearing as a relevant marker for non-empirical studies of sperm cryopreservation. Alongside water, spermatozoa interact with calcium (Ca2+) via the main Ca2+ sperm channel CatSper. Increments in intracellular Ca2+ initiate motility hyperactivation and the acrosome reaction. The four subunits of the CatSper channel were present in boar spermatozoa, mediating changes in sperm motility under in vitro capacitation-inducing conditions (increased extracellular Ca2+ availability and bicarbonate) or challenge by the CatSper antagonists mibefradil and NNC 55-0396. Uterine and oviduct fluids are richest in endogenous opioids as β-endorphins during mating and ovulation. Both μ- and δ- opioid receptors were present in boar spermatozoa modulating sperm motility, as in vitro challenge with known agonists (μ: morphine; δ: DPDPE and κ: U 50488) and antagonists (μ: naloxone; δ: naltrindole and κ: nor-binaltrorphimine) showed that the μ-opioid receptor maintained or increased motility while the δ-opioid receptor mediated decreased motility over time. Finally, boar spermatozoa depicted dose-response effects on sperm kinematics and mitochondrial potential following in vitro challenge with 130 pharmacological drugs and toxic compounds as well as with eight known mito-toxic compounds. In conclusion, boar spermatozoa expressing functional water (AQPs-7 and -9) and ion (CatSper 1-4) channels as well as μ- and δ-opioid receptors are able to adapt to stressful environmental variations, capacitation and pharmacological compounds and drug components. Ejaculated sperm suspensions are easily and painlessly obtained from breeding boars, and are suitable biosensors for in vitro drug-induced testing, complying with the 3R principles of reduction and replacement of experimental animals, during early toxicology screening.
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| 2. |
- Rådjursöga, Millie, 1977, et al.
(författare)
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The H-1 NMR serum metabolomics response to a two meal challenge: a cross-over dietary intervention study in healthy human volunteers
- 2019
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Ingår i: Nutrition Journal. - : Springer Science and Business Media LLC. - 1475-2891. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Metabolomics represents a powerful tool for exploring modulation of the human metabolome in response to food intake. However, the choice of multivariate statistical approach is not always evident, especially for complex experimental designs with repeated measurements per individual. Here we have investigated the serum metabolic responses to two breakfast meals: an egg and ham based breakfast and a cereal based breakfast using three different multivariate approaches based on the Projections to Latent Structures framework. Methods: In a cross over design, 24 healthy volunteers ate the egg and ham breakfast and cereal breakfast on four occasions each. Postprandial serum samples were subjected to metabolite profiling using H-1 nuclear magnetic resonance spectroscopy and metabolites were identified using 2D nuclear magnetic resonance spectroscopy. Metabolic profiles were analyzed using Orthogonal Projections to Latent Structures with Discriminant Analysis and Effect Projections and ANOVA-decomposed Projections to Latent Structures. Results: The Orthogonal Projections to Latent Structures with Discriminant Analysis model correctly classified 92 and 90% of the samples from the cereal breakfast and egg and ham breakfast, respectively, but confounded dietary effects with inter-personal variability. Orthogonal Projections to Latent Structures with Effect Projections removed inter-personal variability and performed perfect classification between breakfasts, however at the expense of comparing means of respective breakfasts instead of all samples. ANOVA-decomposed Projections to Latent Structures managed to remove inter-personal variability and predicted 99% of all individual samples correctly. Proline, tyrosine, and N-acetylated amino acids were found in higher concentration after consumption of the cereal breakfast while creatine, methanol, and isoleucine were found in higher concentration after the egg and ham breakfast. Conclusions: Our results demonstrate that the choice of statistical method will influence the results and adequate methods need to be employed to manage sample dependency and repeated measurements in cross-over studies. In addition, H-1 nuclear magnetic resonance serum metabolomics could reproducibly characterize postprandial metabolic profiles and identify discriminatory metabolites largely reflecting dietary composition.
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| 3. |
- Lundälv, Jörgen, 1966
(författare)
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Bioterrorism och media
- 2004
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Attacker med biologiska och kemiska preparat är ett nytt hot mot institutioner i världen bl.a massmedia. I USA har ett antal medieföretag attackerats med brev som visat sig innehålla mjältbrand. I Sverige utsätts medier för hot och risker med jämna mellanrum. Denna guide om säkerhet och beredskap ger ny kunskap om vad bioterrorism innebär och vilka hotbilder som finns mot medieföretag i Sverige. Den vänder sig också till informationsstrateger vid myndigheter och företag liksom till hälso- och sjukvårdspersonal med intresse för epidemiologiska frågor. Guiden inleds med företal av Gorm Albrechtsen, f.d. chefredaktör vid Herning Folkeblad i Danmark som utsatts för misstänkta pulverbrev samt av Åke Sellström, avdelningschef vid Totalförsvarets forskningsinstitut (FOI) och expert på biologiska och kemiska vapen.
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| 4. |
- Held, Felix, et al.
(författare)
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Modelling of oscillatory cortisol response in horses using a Bayesian population approach for evaluation of dexamethasone suppression test protocols
- 2019
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Ingår i: Journal of Pharmacokinetics and Pharmacodynamics. - : Springer Science and Business Media LLC. - 1567-567X .- 1573-8744. ; 46:1, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Cortisol is a steroid hormone relevant to immune function in horses and other species and shows a circadian rhythm. The glucocorticoid dexamethasone suppresses cortisol in horses. Pituitary pars intermedia dysfunction (PPID) is a disease in which the cortisol suppression mechanism through dexamethasone is challenged. Overnight dexamethasone suppression test (DST) protocols are used to test the functioning of this mechanism and to establish a diagnosis for PPID. However, existing DST protocols have been recognized to perform poorly in previous experimental studies, often indicating presence of PPID in healthy horses. This study uses a pharmacokinetic/pharmacodynamic (PK/PD) modelling approach to analyse the oscillatory cortisol response and its interaction with dexamethasone. Two existing DST protocols were then scrutinized using model simulations with particular focus on their ability to avoid false positive outcomes. Using a Bayesian population approach allowed for quantification of uncertainty and enabled predictions for a broader population of horses than the underlying sample. Dose selection and sampling time point were both determined to have large influence on the number of false positives. Advice on pitfalls in test protocols and directions for possible improvement of DST protocols were given. The presented methodology is also easily extended to other clinical test protocols.
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| 5. |
- Ekstrand, Carl, et al.
(författare)
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Plasma concentration-dependent suppression of endogenous hydrocortisone in the horse after intramuscular administration of dexamethasone-21-isonicotinate
- 2015
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Ingår i: Journal of Veterinary Pharmacology and Therapeutics. - : Wiley. - 0140-7783 .- 1365-2885. ; 38:3, s. 235-242
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Tidskriftsartikel (refereegranskat)abstract
- Detection times and screening limits (SL) are methods used to ensure that the performance of horses in equestrian sports is not altered by drugs. Drug concentration-response relationship and knowledge of concentration-time profiles in both plasma and urine are required. In this study, dexamethasone plasma and urine concentration-time profiles were investigated. Endogenous hydrocortisone plasma concentrations and their relationship to dexamethasone plasma concentrations were also explored. A single dose of dexamethasone-21-isonicotinate suspension (0.03mg/kg) was administered intramuscularly to six horses. Plasma was analysed for dexamethasone and hydrocortisone and urine for dexamethasone, using UPLC-MS/MS. Dexamethasone was quantifiable in plasma for 8.3 +/- 2.9days (LLOQ: 0.025g/L) and in urine for 9.8 +/- 3.1days (LLOQ: 0.15g/L). Maximum observed dexamethasone concentration in plasma was 0.61 +/- 0.12g/L and in urine 4.2 +/- 0.9g/L. Terminal plasma half-life was 38.7 +/- 19h. Hydrocortisone was significantly suppressed for 140h. The plasma half-life of hydrocortisone was 2.7 +/- 1.3h. Dexamethasone potency, efficacy and sigmoidicity factor for hydrocortisone suppression were 0.06 +/- 0.04g/L, 0.95 +/- 0.04 and 6.2 +/- 4.6, respectively. Hydrocortisone suppression relates to the plasma concentration of dexamethasone. Thus, determination of irrelevant plasma concentrations and SL is possible. Future research will determine whether hydrocortisone suppression can be used as a biomarker of the clinical effect of dexamethasone.
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| 6. |
- Liu, Yuanhua, 1971, et al.
(författare)
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Usability Tests as a Benchmarking Tool - A Case Study on Complex Medical Ventilators
- 2009
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Ingår i: Contemporary Ergonomics 2009. - 9780415804332 ; , s. 182-188
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Konferensbidrag (refereegranskat)abstract
- Medical ergonomics has become an important topic in the field of ergonomics due to the increasing deficiencies in medical device design. The aim of the present study was to use usability testing as a benchmarking tool of modern and complex ventilator machines in a real hospital setting to propose future redesign ideas for a target machine – SERVO-i. A usability study was carried out at the neonatal intensive care unit (ICU) with 6 expert nurses. During the tests, an artificial lung was used to simulate the real treatment context on a neonatal patient. A number of potential usability problems were detected on SERVO-i. Using Babylog and Stephanie as two reference machines, the strengths and weaknesses of SERVO-i were identified as well. Some valuable lessons were learnt from the study, which could be used as guidance for the choice of test subjects and control of tests in real life human-machine working environments.
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| 7. |
- Andersson, Helene, 1983, et al.
(författare)
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Effects of molecular weight on permeability and microstructure of mixed ethyl-hydroxypropyl-cellulose films
- 2013
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Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 48:1-2, s. 240-248
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Tidskriftsartikel (refereegranskat)abstract
- Films of ethyl cellulose (EC) and water-soluble hydroxypropyl cellulose (HPC) can be used for extended release coatings in oral formulations. The permeability and microstructure of free EC/HPC films with 30% w/w HPC were studied to investigate effects of EC molecular weight. Phase separation during film spraying and subsequent HPC leaching after immersion in aqueous media cause pore formation in such films. It was found that sprayed films were porous throughout the bulk of the films after water immersion. The molecular weight affected HPC leaching, pore morphology and film permeability; increasing the molecular weight resulted in decreasing permeability. A model to distinguish the major factors contributing to diffusion retardation in porous films showed that the trend in permeability was determined predominantly by factors associated with the geometry and arrangement of pores, independent of the diffusing species. The film with the highest molecular weight did, however, show an additional contribution from pore wall/permeant interactions. In addition, rapid drying and increasing molecular weight resulted in smaller pores, which suggest that phase separation kinetics affects the final microstructure of EC/HPC films. Thus, the molecular weight influences the microstructural features of pores, which are crucial for mass transport in EC/HPC films.
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| 8. |
- Di Pede, Giuseppe, et al.
(författare)
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Revisiting the bioavailability of flavan-3-ols in humans: A systematic review and comprehensive data analysis
- 2023
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Ingår i: Molecular Aspects of Medicine. - : Elsevier BV. - 1872-9452 .- 0098-2997. ; 89
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Forskningsöversikt (refereegranskat)abstract
- This systematic review summarizes findings from human studies investigating the different routes of absorption, metabolism, distribution and excretion (ADME) of dietary flavan-3-ols and their circulating metabolites in healthy subjects. Literature searches were performed in PubMed, Scopus and the Web of Science. Human intervention studies using single and/or multiple intake of flavan-3-ols from food, extracts, and pure compounds were included. Forty-nine human intervention studies met inclusion criteria. Up to 180 metabolites were quantified from blood and urine samples following intake of flavan-3-ols, mainly as phase 2 conjugates of microbial catabolites (n = 97), with phenyl-γ-valerolactones being the most representative ones (n = 34). Phase 2 conjugates of monomers and phenyl-γ-valerolactones, the main compounds in both plasma and urine, reached two peak plasma concentrations (Cmax) of 260 and 88 nmol/L at 1.8 and 5.3 h (Tmax) after flavan-3-ol intake. They contributed to the bioavailability of flavan-3-ols for over 20%. Mean bioavailability for flavan-3-ols was moderate (31 ± 23%, n bioavailability values = 20), and it seems to be scarcely affected by the amount of ingested compounds. While intra- and inter-source differences in flavan-3-ol bioavailability emerged, mean flavan-3-ol bioavailability was 82% (n = 1) and 63% (n = 2) after (−)-epicatechin and nut (hazelnuts, almonds) intake, respectively, followed by 25% after consumption of tea (n = 7), cocoa (n = 5), apples (n = 3) and grape (n = 2). This highlights the need to better clarify the metabolic yield with which monomer flavan-3-ols and proanthocyanidins are metabolized in humans. This work clarified in a comprehensive way for the first time the ADME of a (poly)phenol family, highlighting the pool of circulating compounds that might be determinants of the putative beneficial effects linked to flavan-3-ol intake. Lastly, methodological inputs for implementing well-designed human and experimental model studies were provided.
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| 9. |
- Larsson, Mikael, 1982, et al.
(författare)
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Effect of ethanol on the water permeability of controlled release films composed of ethyl cellulose and hydroxypropyl cellulose
- 2010
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Ingår i: European Journal of Pharmaceutics and Biopharmaceutics. - : Elsevier BV. - 1873-3441 .- 0939-6411. ; 76:3, s. 428-432
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Tidskriftsartikel (refereegranskat)abstract
- The robustness of controlled release formulations when co-ingested with alcohol is a current concern expressed by regulatory authorities, especially with regard to dose dumping. One such controlled release formulation commonly used is film coating composed of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC). The aim of this study was to investigate how the presence of ethanol in the dissolution medium affects the water permeability of such films. Film samples were prepared in various EC–HPC compositions, and the effect of different ethanol concentrations in the dissolution medium on the permeability was studied using a modified Ussing chamber and tritiated water. It was found that the effect of ethanol on the film permeability varied depending on the composition of the films. The results were interpreted in terms of swelling of the EC in the films, where the swelling increased with increasing ethanol concentration. Thus, for films with low HPC content (non-interconnected pores), the water permeability of the films increased with increasing ethanol concentration as the diffusion through the ethyl cellulose increased due to swelling. However, for films with higher HPC content (having interconnected pores through the films), the permeability decreased, likely due to the swelling of the ethyl cellulose blocking the pores. The interpretation of the results was supported by dynamic mechanic analysis and SEM analysis.
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| 10. |
- Waqas, Muhammad, 1983, et al.
(författare)
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In vitro models for simulating swallowing
- 2017
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Ingår i: Medical radiology. - Cham : Springer International Publishing. - 9783319685717 ; , s. 549-562, s. 549-562
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter gives an overview of the in vitro models that are currently used for studying swallowing. The focus is on the construction, geometry, and performance of mechanical models. Swallowing simulations and mathematical modeling are also considered. The in vitro models that are concerned with the oral, pharyngeal, and esophageal phases of swallowing linked to bolus properties are discussed. The pharyngeal phase is given special consideration, as it is involved in both food transport to the stomach and air transport to the lungs, and therefore constitutes the most critical phase of swallowing.
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