1.
Hedeland, Mikael, et al.
(författare)
Confirmation of botulism in birds and cattle by the mouse bioassay and Endopep-MS
2011
Ingår i: Journal of Medical Microbiology. - : Microbiology Society. - 0022-2615 .- 1473-5644. ; 60:9, s. 1299-1305
Tidskriftsartikel (refereegranskat) abstract
There have been several outbreaks of botulism among poultry and wild birds in Sweden in recent years. The National Veterinary Institute of Sweden (SVA) has identified botulinum neurotoxin (BoNT)/C1 or the mosaic BoNT/C1D using the mouse bioassay. This is believed to be the first report on the application of the Endopep mass spectrometry (Endopep-MS) method to selected clinical animal (serum and liver) samples and a feed sample that had previously given positive test results with the mouse bioassay. In the mouse bioassay eight of the eleven samples were found to be neutralized by both BoNT/C1 and /D antitoxins; the other three were neutralized only by BoNT/C1 antitoxin, but the mice showed a prolonged survival time when the samples had been treated with /D antitoxin. The Endopep-MS analysis, on the other hand, demonstrated only BoNT/C1 activity for all eleven samples. This suggests that at least eight of the samples were of the chimeric toxin type BoNT/C1D, where the enzymically active site is identical to that of BoNT/C1, while other parts of the protein contain sequences of BoNT/D. This is the first step of a cross-validation between the established mouse bioassay and the Endopep-MS of serotypes BoNT/C1 and /C1D. Endopep-MS is concluded to have potential as an attractive alternative to the mouse bioassay.
2.
3.
Rydevik, Axel, 1984-
(författare)
Drug Metabolites Formed by Cunninghamella Fungi : Mass Spectrometric Characterization and Production for use in Doping Control
2014
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
This thesis describes the in vitro production of drug metabolites using fungi of the Cunninghamella species. The metabolites were characterized with mainly liquid chromatography-mass spectrometry using ion-trap and quadrupole-time-of-flight instruments. A fungal in vitro model has several advantages e.g., it is easily up-scaled and ethical problems associated with animal-based models are avoided.The metabolism of bupivacaine and the selective androgen receptor modulators (SARMs) S1, S4 and S24 by the fungi Cunninghamella elegans and Cunninghamella blakesleeana was investigated. The detected metabolites were compared with those formed in vitro and in vivo by human and horse and most phase I metabolites formed by mammals were also formed by the fungi. The higher levels of bupivacaine metabolites in the fungal samples allowed an extensive mass spectrometric structural characterization which shows that the fungi are relevant metabolic models.Glucuronides are important drug metabolites but they are difficult to synthesize. The discovery that the fungus Cunninghamella elegans formed large amounts of glucosides led to the idea that they could be used to form glucuronides. A new concept was developed where a fungal incubate containing a SARM S1 glucoside was mixed with the free radical tetramethylpiperidinyl-1-oxy (TEMPO), sodium bromide and sodium hypochlorite which produced a glucuronide. Isolation and characterization by nuclear magnetic resonance spectroscopy proved that the new method could produce glucuronides for use as reference material.An investigation of reactive metabolite formation of the drugs paracetamol, mefenamic acid and diclofenac by the fungus Cunninghamella elegans was performed. It was demonstrated for the first time that the fungus could produce glutathione, glutathione ethyl-ester, cysteine and N-acetylcysteine conjugates that are indicative of a preceding formation of reactive intermediates. A comparison with conjugates formed by human liver microsomes showed that both models formed identical metabolites.The presented investigations prove that Cunninghamella fungi are relevant drug metabolism models. They show that the fungi to a large extent forms the same metabolites as mammals and that they can produce metabolites for use as reference material in, e.g. doping control. It was also demonstrated that the fungal model can be used in the important assessment of drug toxicity.
4.
Rydevik, Axel, et al.
(författare)
The fungus Cunninghamella elegans can produce human and equine metabolites of selective androgen receptor modulators (SARMs)
2013
Ingår i: Xenobiotica. - : Informa UK Limited. - 0049-8254 .- 1366-5928. ; 43:5, s. 409-420
Tidskriftsartikel (refereegranskat) abstract
1. Selective androgen receptor modulators (SARMs) are a group of substances that have potential to be used as doping agents in sports. Being a relatively new group not available on the open market means that no reference materials are commercially available for the main metabolites. In the presented study, the in vitro metabolism of SARMs by the fungus Cunninghamella elegans has been investigated with the purpose of finding out if it can produce relevant human and equine metabolites.2. Three different SARMs, S1, S4 and S24, were incubated for 5 days with C. elegans. The samples were analysed both with and without sample pretreatment using ultra performance liquid chromatography coupled to high resolution mass spectrometry.3. All the important phase I and some phase II metabolites from human and horse were formed by the fungus. They were formed through reactions such as hydroxylation, deacetylation, O-dephenylation, nitro-reduction, acetylation and sulfonation.4. The study showed that the fungus produced relevant metabolites of the SARMs and thus can be used to mimic mammalian metabolism. Furthermore, it has the potential to be used for future production of reference material.
5.
6.
Ekstrand, Carl, et al.
(författare)
Plasma concentration-dependent suppression of endogenous hydrocortisone in the horse after intramuscular administration of dexamethasone-21-isonicotinate
2015
Ingår i: Journal of Veterinary Pharmacology and Therapeutics. - : Wiley. - 0140-7783 .- 1365-2885. ; 38:3, s. 235-242
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.
7.
Kullenberg, Fredrik, et al.
(författare)
In Vitro Cell Toxicity and Intracellular Uptake of Doxorubicin Exposed as a Solution or Liposomes : Implications for Treatment of Hepatocellular Carcinoma
2021
Ingår i: Cells. - : MDPI. - 2073-4409. ; 10:7
Tidskriftsartikel (refereegranskat) abstract
Cytostatic effects of doxorubicin in clinically applied doses are often inadequate and limited by systemic toxicity. The main objective of this in vitro study was to determine the anti-tumoral effect (IC50) and intracellular accumulation of free and liposomal doxorubicin (DOX) in four human cancer cell lines (HepG2, Huh7, SNU449 and MCF7). The results of this study showed a correlation between longer DOX exposure time and lower IC50 values, which can be attributed to an increased cellular uptake and intracellular exposure of DOX, ultimately leading to cell death. We found that the total intracellular concentrations of DOX were a median value of 230 times higher than the exposure concentrations after exposure to free DOX. The intracellular uptake of DOX from solution was at least 10 times higher than from liposomal formulation. A physiologically based pharmacokinetic model was developed to translate these novel quantitative findings to a clinical context and to simulate clinically relevant drug concentration-time curves. This showed that a liver tumor resembling the liver cancer cell line SNU449, the most resistant cell line in this study, would not reach therapeutic exposure at a standard clinical parenteral dose of doxorubicin (50 mg/m(2)), which is serious limitation for this drug. This study emphasizes the importance of in-vitro to in-vivo translations in the assessment of clinical consequence of experimental findings.
8.
Askar, Raad, et al.
(författare)
Bioavailability of subcutaneous and intramuscular administrated buprenorphine in New Zealand White rabbits
2020
Ingår i: BMC Veterinary Research. - : Springer Science and Business Media LLC. - 1746-6148. ; 16:1
Tidskriftsartikel (refereegranskat) abstract
BackgroundBuprenorphine is one of the most used analgesics for postoperative pain in rabbits. The recommended dose in rabbits (0.01–0.05 mg/kg) is the same for intravenous (IV), intramuscular (IM), and subcutaneous (SC) administration, despite lack of pharmacokinetic data. Five male and five female New Zealand White rabbits (mean ± SD body weight 3.1 ± 0.3 kg) were administered 0.05 mg/kg buprenorphine by the IV, IM and SC routes and 0.1 mg/kg by the SC route, in a cross-over design with two-week wash-out periods between treatments. Blood was collected before, and up to 8 h post buprenorphine injection, for determination of serum levels by UPHLC-MS/MS.ResultsThe area under the time concentration curve (AUC0-t) was lower after SC (398 ± 155 ng/mL/min) than IM (696 ± 168 ng/mL/min, p < 0.001) and IV (789 ± 189 ng/mL/min, p < 0.001) administration. The maximum serum concentration was lower after SC (2.2 ± 1.4 ng/mL) than after IM (11 ± 3.2 ng/mL) administration (p < 0.001). The bioavailability was lower after SC (50 ± 19%) than after IM (95 ± 21%) administration (p = 0.006). The elimination half-life was longer after SC (260 ± 120 min) than after IM (148 ± 26 min, p = 0.002) as well as IV (139 ± 33 min) injection (p < 0.001). An increase in the SC dose from 0.05 to 0.1 mg/kg resulted in an increase in the area under the time concentration curve of 50% in female (p = 0.022) and 165% in male rabbits (p < 0.001). The bioavailability did not change in the females (36 ± 14%, p = 0.6), whereas it increased in the males (71 ± 23%, p = 0.008).ConclusionsThe lower bioavailability of 0.05 mg/kg buprenorphine after SC administration could explain the lack of efficacy seen in clinical pain studies in rabbits, using this route. For immediate pain relief, IV or IM administration is therefore be recommended, whereas SC administration may be useful to sustain analgesic serum levels, once efficient pain relief has been achieved. The current data do not support an increase in dose to compensate for the lower SC bioavailability.
9.
Bergman, Ebba, 1977-, et al.
(författare)
Effect of a Single Gemfibrozil Dose on the Pharmacokinetics of Rosuvastatin in Bile and Plasma in Healthy Volunteers
2010
Ingår i: Journal of clinical pharmacology. - : Wiley. - 0091-2700 .- 1552-4604. ; 50:9, s. 1039-1049
Tidskriftsartikel (refereegranskat) abstract
The effect of a single intrajejunal dose of gemfibrozil (600 mg) on the plasma pharmacokinetics and biliary excretion of a single intrajejunal dose of rosuvastatin (20 mg) was investigated by using a multichannel catheter positioned in the distal duodenum/proximal jejunum in eight healthy volunteers. Bile and plasma samples were collected every 20 min for 200 min, with additional plasma samples being withdrawn for up to 48 hrs. Gemfibrozil did not affect the bioavailability of rosuvastatin, although it increased the apparent absorption phase during the initial 200 minutes (AUC0-200) by 1.56-fold (95%CI: 1.14-2.15). The interaction was less pronounced in this single dose study than in a previous report when gemfibrozil was administered repeatedly, nevertheless, the interaction coincided with the highest exposure to gemfibrozil. The plausible reason why the interaction in this investigation was only minor is the low exposure to gemfibrozil (and its metabolites), suggesting that the total plasma concentration of gemfibrozil needs to be above 20 µM in order to affect the disposition of rosuvastatin. This study demonstrates the value of monitoring the plasma pharmacokinetics of the inhibitor, and not only the drug under investigation, to improve the mechanistic interpretation.
10.
Bergman, Ebba, 1977-, et al.
(författare)
The Effect of Acute Administration of Rifampicin and Imatinib on the Enterohepatic Transport of Rosuvastatin In Vivo
2010
Ingår i: Xenobiotica. - : Informa UK Limited. - 0049-8254 .- 1366-5928. ; 40:8, s. 558-568
Tidskriftsartikel (refereegranskat) abstract
Hepatobiliary transporters efficiently shunt rosuvastatin from the blood stream, into the hepatocyte, followed by transporter-mediated excretion into the bile ducts. This study aimed at investigating the contribution of sinusoidal versus canalicular transport on the pharmacokinetics of an intrajejunal dose of 80mg rosuvastatin in pigs (control group, n=2+6). The transport inhibitors, rifampicin (20mg/kg, n6) and imatinib (14mg/kg, n6), were administered as 2-h long intravenous infusions. Plasma samples were withdrawn from the portal and hepatic vein simultaneously during 5h along with bile sample collection. Rifampicin reduced the hepatic extraction of rosuvastatin by 35% and the area under the curve in the hepatic vein compartment increased by a factor of 6.3 (95% confidence intervals (CI): 3.132, P value <0.01). The increase in the portal vein compartment was less pronounced than in the hepatic vein, 2.0-fold (95% CI: 1.13.8, P value <0.05), suggesting that the inhibition was predominantly located in the liver rather than in the intestine and suggesting inhibition if sinusoidal transport. In contrast, no effect on the pharmacokinetics of rosuvastatin was observed following concomitant administration with imatinib possibly due to insufficient concentration of the inhibitor inside the hepatocyte. Rifampicin significantly affected the hepatobiliary transport of rosuvastatin, however imatinib did not alter the plasma exposure of rosuvastatin.
