1.
Rhodin, Malin M., et al.
(författare)
Human renal function maturation: a quantitative description using weight and postmenstrual age
2009
Ingår i: Pediatric Nephrology. - : Springer. - 1432-198X .- 0931-041X. ; 24:1, s. 67-76
Tidskriftsartikel (refereegranskat) abstract
This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, Cr-51-EDTA, mannitol or iohexol) from eight studies (n=923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117-125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95% CI 45.1-50.5), with a Hill coefficient of 3.40 (95% CI 3.03-3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.
2.
Wallén-Mackenzie, Åsa, et al.
(författare)
Restricted cortical and amygdaloid removal of vesicular glutamate transporter 2 in preadolescent mice impacts dopaminergic activity and neuronal circuitry of higher brain function.
2009
Ingår i: The Journal of neuroscience : the official journal of the Society for Neuroscience. - 1529-2401 .- 0270-6474. ; 29:7, s. 2238-51
Tidskriftsartikel (refereegranskat) abstract
A major challenge in neuroscience is to resolve the connection between gene functionality, neuronal circuits, and behavior. Most, if not all, neuronal circuits of the adult brain contain a glutamatergic component, the nature of which has been difficult to assess because of the vast cellular abundance of glutamate. In this study, we wanted to determine the role of a restricted subpopulation of glutamatergic neurons within the forebrain, the Vglut2-expressing neurons, in neuronal circuitry of higher brain function. Vglut2 expression was selectively deleted in the cortex, hippocampus, and amygdala of preadolescent mice, which resulted in increased locomotor activity, altered social dominance and risk assessment, decreased sensorimotor gating, and impaired long-term spatial memory. Presynaptic VGLUT2-positive terminals were lost in the cortex, striatum, nucleus accumbens, and hippocampus, and a downstream effect on dopamine binding site availability in the striatum was evident. A connection between the induced late-onset, chronic reduction of glutamatergic neurotransmission and dopamine signaling within the circuitry was further substantiated by a partial attenuation of the deficits in sensorimotor gating by the dopamine-stabilizing antipsychotic drug aripiprazole and an increased sensitivity to amphetamine. Somewhat surprisingly, given the restricted expression of Vglut2 in regions responsible for higher brain function, our analyses show that VGLUT2-mediated neurotransmission is required for certain aspects of cognitive, emotional, and social behavior. The present study provides support for the existence of a neurocircuitry that connects changes in VGLUT2-mediated neurotransmission to alterations in the dopaminergic system with schizophrenia-like behavioral deficits as a major outcome.
3.
Bengtsson, Jörgen, et al.
(författare)
The influence of age on the distribution of morphine and morphine-3-glucuronide across the blood-brain barrier in sheep
2009
Ingår i: British Journal of Pharmacology. - : Wiley. - 1476-5381 .- 0007-1188. ; 157:6, s. 96-1085
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND AND PURPOSE: The effect of age on the distribution of morphine and morphine-3-glucuronide (M3G) across the blood-brain barrier (BBB) was studied in a sheep model utilizing intracerebral microdialysis. The effect of neonatal asphyxia on brain drug distribution was also studied.EXPERIMENTAL APPROACH: Microdialysis probes were inserted into the cortex, striatum and blood of 11 lambs (127 gestation days) and six ewes. Morphine, 1 mg x kg(-1), was intravenously administered as a 10 min constant infusion. Microdialysis and blood samples were collected for up to 360 min and analysed using liquid chromatography-tandem mass spectrometry. The half-life, clearance, volume of distribution, unbound drug brain : blood distribution ratio (K(p,uu)) and unbound drug volume of distribution in brain (V(u,brain)) were estimated.KEY RESULTS: Morphine K(p,uu) was 1.19 and 1.89 for the sheep and premature lambs, respectively, indicating that active influx into the brain decreases with age. Induced asphyxia did not affect transport of morphine or M3G across the BBB. Morphine V(u,brain) measurements were higher in sheep than in premature lambs. The M3G K(p,uu) values were 0.27 and 0.17 in sheep and premature lambs, indicating a net efflux from the brain in both groups.CONCLUSIONS AND IMPLICATIONS: The morphine K(p,uu) was above unity, indicating active transport into the brain; influx was significantly higher in premature lambs than in adult sheep. These results in sheep differ from those in humans, rats, mice and pigs where a net efflux of morphine from the brain is observed.
4.
Jia, Juan, et al.
(författare)
Lack of L-iduronic acid in heparan sulfate affects interaction with growth factors and cell signaling
2009
Ingår i: Journal of Biological Chemistry. - : American Society for Biochemistry and Molecular Biology. - 0021-9258 .- 1083-351X. ; 284:23, s. 15942-15950
Tidskriftsartikel (refereegranskat) abstract
Glucuronyl C5-epimerase (Hsepi) catalyzes the conversion of D-glucuronic acid to L-iduronic acid in heparan sulfate (HS) biosynthesis. Disruption of the Hsepi gene in mouse yielded a lethal phenotype with selective organ defects, but had remarkably little effect on other organ systems. We have approached the underlying mechanisms by examining the course and effects of FGF2 signaling in a mouse embryonic fibroblast (MEF) cell line derived from the Hsepi-/- mouse. The HS produced by these cells is devoid of IdoA residues, but shows upregulated N- and 6-O-sulfation compared to wildtype (WT) MEF HS. In medium fortified with 10% FCS the Hsepi-/- MEFs proliferated and migrated similar to WT cells. Under starvation conditions both cell types showed attenuated proliferation and migration, that could be restored by addition of FGF2 to WT cells whereas Hsepi-/- cells were resistant. Moreover, ERK phosphorylation following FGF2 stimulation was delayed in Hsepi-/- compared to WT cells. Assessment of HS-growth factor interaction by nitrocellulose filter trapping revealed strikingly aberrant binding property of FGF2 and glia-derived neurotropic factor (GDNF) to Hsepi-/- but not to WT HS. GDNF has a key role in kidney development, defective in Hsepi-/- mice. By contrast, Hsepi-/- and WT HS interacted similarly and in conventional mode with FGF10. These findings correlate defective function of growth factors with their mode of HS interaction, and may help explain the partly modest organ phenotypes observed after genetic ablation of selected enzymes in HS biosynthesis.
5.
Lacroix, Brigitte, 1978-, et al.
(författare)
A Pharmacodynamic Markov Mixed-Effects Model for Determining the Effect of Exposure to Certolizumab Pegol on the ACR20 Score in Patients With Rheumatoid Arthritis
2009
Ingår i: Clinical Pharmacology and Therapeutics. - : Nature Publishing Group. - 0009-9236 .- 1532-6535. ; 86:4, s. 387-395
Tidskriftsartikel (refereegranskat) abstract
The American College of Rheumatology 20% preliminary definition of improvement of rheumatoid arthritis (ACR20) is widely used in clinical trials to assess response to treatment. The objective of this analysis was to develop an exposure-response model of ACR20 in subjects treated with certolizumab pegol, and to predict clinical outcome following various treatment schedules. At each visit, subjects were classified as being ACR20 responders, ACR20 non-responders, or having dropped out. A Markov mixed-effect model was developed to investigate the drug effect on the transitions between the 3 defined states. Increasing certolizumab pegol exposure predicted an increasing probability of becoming a responder and remaining a responder, as well as a reduced probability of dropping out of treatment. Simulations of the ACR20 response rate support dosing regimens of 400 mg at weeks 0, 2 and 4 followed by 200 mg every 2 weeks, or alternative maintenance regimen of 400 mg every 4 weeks.
6.
Wallin, Johan E., et al.
(författare)
A tool for neutrophil guided dose adaptation in chemotherapy
2009
Ingår i: Computer Methods and Programs in Biomedicine. - : Elsevier BV. - 0169-2607 .- 1872-7565. ; 93:3, s. 283-291
Tidskriftsartikel (refereegranskat) abstract
Chemotherapy dosing in anticancer treatment is a balancing act between achieving concentrations that are effective towards the malignancy and that result in acceptable side-effects. Neutropenia is one major side-effect of many antitumor agents, and is related to an increased risk of infection. A model capable of describing the time-course of myelosuppression from administered drug could be used in individual dose selection. In this paper we describe the transfer of a previously developed semi-mechanistic model for myelosuppression from NONMEM to a dosing tool in MS Excel, with etoposide as an example. The tool proved capable to solve a differential equation system describing the pharmacokinetics and pharmacodynamics, with estimation performance comparable to NONMEM. In the dosing tool the user provides neutrophil measures from a previous treatment course and request for the dose that results in a desired nadir in the upcoming course through a Bayesian estimation procedure.
7.
Ahlin, Gustav, 1977-, et al.
(författare)
Endogenous Gene and Protein Expression of Drug Transporting Proteins in Cell Lines Routinely used in Drug Discovery Programs
2009
Ingår i: Drug Metabolism And Disposition. - : American Society for Pharmacology & Experimental Therapeutics (ASPET). - 0090-9556 .- 1521-009X. ; 37:12, s. 2275-2283
Tidskriftsartikel (refereegranskat) abstract
The aim of this study was to investigate the gene and protein expression profiles of important drug transporting proteins in human cell lines commonly used for studies of drug transport mechanisms. Human cell lines used to transiently or stably express single transporters (HeLa, HEK293) and leukaemia cell lines used to study drug resistance by ABC-transporters (HL-60, K562) were investigated, and compared with organotypic cell lines (HepG2, Saos-2, Caco-2 and Caco-2 TC7). For gene expression studies, real-time PCR was used, while monospecific polyclonal antibodies were generated and used to investigate protein expression by immunohistochemistry. Thirty-six transporters were studied for gene expression and nine for protein expression. The antibodies were validated using expression patterns in human tissues. Finally, the function of one ubiquitously expressed transporter, MCT1; SLC16A1 was investigated using 14C-lactic acid as a substrate. In general, the adherent cell lines (HeLa, HEK293) displayed low transporter expression and the expression patterns were barely affected by transfection. The leukaemia cell lines (K562, HL-60) and Saos-2 also had low endogenous transporter expression, while the organotypic cell lines (HepG2 and Caco-2) showed higher expression of some transporters. Comparison of gene and protein expression profiles gave poor correlations, but better agreement was obtained for antibodies with a good validation score, indicating that antibody quality was a significant variable. Importantly, the monocarboxylic acid transporting protein MCT1 was significantly expressed in all, and functional in most of the cell lines, indicating that MCT1 may be a confounding factor when the transport of small anionic drugs is investigated.
8.
Ahlin, Gustav, 1977-
(författare)
In vitro and in silico prediction of drug-drug interactions with transport proteins
2009
Doktorsavhandling (övrigt vetenskapligt) abstract
Drug transport across cells and cell membranes in the human body is crucial for the pharmacological effect of drugs. Active transport governed by transport proteins plays an important role in this process. A vast number of transport proteins with a wide tissue distribution have been identified during the last 15 years. Several important examples of their role in drug disposition and drug-drug interactions have been described to date. Investigation of drug-drug interactions at the transport protein level are therefore of increasing interest to the academic, industrial and regulatory research communities. The gene expression of transport proteins involved in drug transport was investigated in the jejunum, liver, kidney and colon to better understand their influence on the ADMET properties of drugs. In addition, the gene and protein expression of transport proteins in cell lines, widely used for predictions of drug transport and metabolism, was examined. The substrate and inhibitor heterogeneity of many transport proteins makes it difficult to foresee whether the transport proteins will cause drug-drug interactions. Therefore, in vitro assays for OCT1 and OATP1B1, among the highest expressed transport proteins in human liver, were developed to allow investigation of the inhibitory patterns of these proteins. These assays were used to investigate two data sets, consisting of 191 and 135 registered drugs and drug-like molecules for the inhibition of OCT1 and OATP1B1, respectively. Numerous new inhibitors of the transport proteins were identified in the data sets and the properties governing inhibition were determined. Further, antidepressant drugs and statins displayed strong inhibition of OCT1 and OATP1B1, respectively. The inhibition data was used to develop predictive in silico models for each of the two transport proteins. The highly polymorphic nature of some transport proteins has been shown to affect drug response and may lead to an increased risk of drug-drug interactions, and therefore, the OCT1 in vitro assay was used to study the effect of common genetic variants of OCT1 on drug inhibition and drug-drug interactions. The results indicated that OCT1 variants with reduced function were more susceptible to inhibition. Further, a drug-drug interaction of potential clinical significance in the genetic OCT1 variant M420del was proposed. In summary, gene expression of transport proteins was investigated in human tissues and cell lines. In vitro assays for two of the highest expressed liver transport proteins were used to identify previously unknown SLC transport protein inhibitors and to develop predictive in silico models, which may detect previously known drug-drug interactions and enable new ones to be identified at the transport protein level. In addition, the effect of genetic variation on inhibition of the OCT1 was investigated.
9.
Akkawi, Ranaa, et al.
(författare)
Effect of oral naloxone hydrochloride on gastrointestinal transit in premature infants treated with morphine
2009
Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 98:3, s. 442-447
Tidskriftsartikel (refereegranskat) abstract
Background: Opioids are common drugs for pain treatment in preterm newborn infants, in spite of several adverse effects. Constipation is a frequent problem when opioids are used in both adults and neonates. Although several studies indicate that the oral administration of naloxone hydrochloride (NH) improves intestinal motility during opioid therapy, there is still a lack of evidence in newborns. Aim: The aim of this study was to assess the efficacy of NH against reduced intestinal motility during opioid treatment. Methods: A retrospective cohort study was performed. We analysed the medical records of fifteen infants (Group 1) treated with continuous morphine (MO) infusion and fourteen infants (Group 2) treated with both oral NH (3 mu g/kg 4 times daily) and MO. Results: There was no statistically significant difference in the total MO dose. Infants treated both with NH and MO had a tendency to improve their mean stool frequency/day. A statistically significant improvement was observed in the mean total food intake (mL/kg/day) of the infants treated with NH (p = 0.014). No difference in the mean food retention between the two groups was observed. Conclusion: Orally administrated NH seems to improve intestinal motility resulting in increased food intake/day and improved stool frequency/day in premature newborn infants treated with MO. Further studies are needed to corroborate these findings.
10.
Alenius, Malin, 1974-
(författare)
Treatment Response in Psychotic Patients in a Naturalistic Setting : Classification, Genes, Drugs, Insight and Social Networks
2009
Doktorsavhandling (övrigt vetenskapligt) abstract
Many patients with psychotic symptoms respond poorly to treatment. Various approaches have been made to classify these patients according to treatment response. However, existing classifications have been criticized for various reasons and a new classification system is needed. Further, no satisfactory explanation of the poor treatment response has been apparent. The general aim of this thesis was therefore to develop and validate a new classification method of functional remission in a naturalistic population of patients with psychosis and to utilize this classification to investigate the population from genetic, drug treatment, insight and social network points of view. Data for this cross-sectional study of patients (n=123) attending the Psychosis Outpatient Care clinic in the county of Jönköping, Sweden, were obtained from patient interviews, blood samples and information from patient files. The new classification method CANSEPT, which combines the CAN rating scale (CAN), the UKU side effect rating scale (SE) and the patient’s previous treatment history (PT), showed validity in discriminating the patients and was accepted well by the patients. CANSEPT was used to group the patients in the other studies in this thesis. The results indicated that the gene polymorphism ABCB1 3435T, was related to worse significant social and clinical needs for patients on olanzapine, while the polymorphism DRD2 Taq1 A1 was related to a greater risk of significant side effects; especially if male, or taking strong dopamine D2-receptor antagonistic drugs. Drug treatment factors were also related to treatment response; longer duration of untreated prodromal and early psychosis was seen for patients with current significant social and clinical needs and non-adherence to treatment was associated with worse significant side effects. Worse treatment outcomes also appeared to be associated with smaller social network groups, worse insight into illness, poorer knowledge of warning signs and worse coping strategies. In summary, CANSEPT was shown to be a useful valid, multidimensional tool for classification of treatment response. Gene polymorphisms, duration of untreated illness, non-adherence to treatment, social networks and knowledge should be taken into consideration when investigating inadequate treatment response.
