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Leif Bertilsson

Other affiliations: Astra, University of Oulu, University of Extremadura  ...read more
Bio: Leif Bertilsson is an academic researcher from Karolinska University Hospital. The author has contributed to research in topics: Debrisoquine & Debrisoquin. The author has an hindex of 87, co-authored 321 publications receiving 23933 citations. Previous affiliations of Leif Bertilsson include Astra & University of Oulu.


Papers
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Journal ArticleDOI
TL;DR: Many drugs, including proton pump inhibitors and certain antidepressants, are metabolized by the polymorphic cytochrome P450 (CYP) 2C19 enzyme, and a significant portion of extensive metabolizers do not reach appropriate drug levels.
Abstract: Background and Objective Many drugs, including proton pump inhibitors and certain antidepressants, are metabolized by the polymorphic cytochrome P450 (CYP) 2C19 enzyme. A significant portion of extensive metabolizers do not reach appropriate drug levels, and our objective was to investigate any genetic background. Methods The 5′-flanking region of the CYP2C19 gene from subjects with rapid omeprazole metabolism was sequenced, and CYP2C19 phenotype-genotype associations were analyzed in Swedish (n=107) and Ethiopian (n=126) extensive metabolizers. The relationship of the metabolic ratio of omeprazole (omeprazole/5-hydroxyomeprazole in plasma 3 hours after drug intake) with the area under the plasma concentration-time curve was used for prediction studies. Electrophoretic mobility shift assays were conducted by use of human nuclear protein extracts. Hepatic reporter vector transfections were carried out in CD1 mice. Results We identified a novel allele (CYP2C19*17) carrying −806C>T and −3402C>T, with a frequency of 18% in both Swedes and Ethiopians and 4% in Chinese subjects. In Swedes the metabolic ratio of omeprazole was higher in subjects homozygous for CYP2C19*1 (median, 0.50 [interquartile range, 0.37–0.73]) than in those homozygous for CYP2C19*17 (median, 0.25 [interquartile range, 0.15–0.33]) (P = .010). In Ethiopians a similar difference in the S/R-mephenytoin ratio was observed between individuals homozygous for CYP2C19*1 (median, 0.20 [interquartile range, 0.12–0.37]) and those homozygous for CYP2C19*17 (median, 0.05 [interquartile range, 0.03–0.06]) (P=.013). Electrophoretic mobility shift assays showed specific binding of human hepatic nuclear proteins to an element carrying −806T but not −806C. Reporter vector experiments showed an increased transcriptional activity of the CYP2C19*17 allele in vivo in mice. Predictions revealed that CYP2C19*17 homozygotes would attain 35% to 40% lower omeprazole area under the plasma concentration-time curve values than subjects homozygous for CYP2C19*1 taking standard doses of omeprazole. Conclusion CYP2C19*17 is likely to cause therapeutic failures in drug treatment with, for example, proton pump inhibitors and antidepressants. Clinical Pharmacology & Therapeutics (2006) 79, 103–113; doi: 10.1016/j.clpt.2005.10.002

716 citations

Journal ArticleDOI
TL;DR: A follow-up study revealed a 20% mortality by suicide within a year after lumbar puncture in patients with a CSF-HIAA level below the median, which was lower than normal in suicidal patients who were not diagnosed as depressed at the time of lumbr puncture.
Abstract: • Cerebrospinal fluid concentrations of the monoamine metabolites 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenyl glycol (MHPG) were measured in 30 psychiatric patients who had attempted suicide and 45 healthy volunteers. The suicide attempters had a significantly lower CSF 5-HIAA level than the controls, especially those who had made more violent attempts. After adjustment for differences in body height and age between controls and patients, the difference in 5-HIAA level became even more marked. Concentrations of 5-HIAA also were lower than normal in suicidal patients who were not diagnosed as depressed at the time of lumbar puncture, while HVA levels were lowered only in the depressives. A follow-up study of these and 89 more patients (depressed and/or suicidal) revealed a 20% mortality by suicide within a year after lumbar puncture in patients with a CSF 5-HIAA level below the median.

668 citations

Journal ArticleDOI
06 Feb 1976-Science
TL;DR: There was a significant correlation between the concnetration of 5-HIAA and severity of depression in the lower, but not in the upper, mode, which suggests the existence of a biochemical subgroup of depressive disorder, characterized by a disturbance of serotonin turnover.
Abstract: The distribution of 5-hydroxyindoleacetic acid (5-HIAA) concentrations in the cerebrospinal fluid of 68 depressed patients was bimodal. Twenty-nine percent of the patients were in the lower mode, with a concentration of 5-HIAA below 15 nanograms per milliliter. Although there were no differences in overall severity of depression between the two modes, there was a significant correlation between the concnetration of 5-HIAA and severity of depression in the lower, but not in the upper, mode. The finding suggests the existence of a biochemical subgroup of depressive disorder, characterized by a disturbance of serotonin turnover.

644 citations

Journal ArticleDOI
TL;DR: The data show the principle of inherited amplification of an active gene, and the finding of a specific haplotype with two or more active CYP2D6 genes allows genotyping for ultrarapid drug metabolizers.
Abstract: Deficient hydroxylation of debrisoquine is an autosomal recessive trait that affects approximately 7% of the Caucasian population. These individuals (poor metabolizers) carry deficient CYP2D6 gene variants and have an impaired metabolism of severely commonly used drugs. The opposite phenomenon also exists, and certain individuals metabolize the drugs very rapidly, resulting in subtherapeutic plasma concentrations at normal doses. In the present study, we have investigated the molecular genetic basis for ultrarapid metabolism of debrisoquine. Restriction fragment length polymorphism analysis of the CYP2D locus in two families with very rapid metabolism of debrisoquine [metabolic ratio (MR) for debrisoquine = 0.01-0.1] revealed the variant CYP2D6 gene CYP2D6L. Eco RI RFLP and Xba I pulsed-field gel electrophoresis analyses showed that this gene had been amplified 12-fold in three members (father and his two children) of one of the families, and two copies were present among members of the other family. The CYP2D6L gene had an open reading frame and carried two mutations causing amino acid substitutions: one in exon 6, yielding an Arg-296-->Cys exchange and one in exon 9 causing Ser-486-->Thr. The MR of subjects carrying one copy of the CYP2D6L gene did not significantly differ from that of those with the wild-type gene, indicating that the structural alterations were not of importance of the catalytic properties of the gene product. Examination of the MR among subjects carrying wild-type CYP2D6, CYP2D6L, or deficient alleles revealed a relationship between the number of active genes and MR. The data show the principle of inherited amplification of an active gene. Furthermore, the finding of a specific haplotype with two or more active CYP2D6 genes allows genotyping for ultrarapid drug metabolizers. This genotyping could be of predictive value for individualized and more efficient drug therapy.

641 citations

Journal ArticleDOI
TL;DR: The present-day knowledge on the influence of the genetic variability in CYP2D6 on the clinical pharmacokinetics and therapeutic effects/adverse effects of psychotropic drugs is reviewed.
Abstract: Cytochrome P450 CYP2D6 is the most extensively characterized polymorphic drug-metabolizing enzyme. A deficiency of the CYP2D6 enzyme is inherited as an autosomal recessive trait; these subjects (7% of Caucasians, about 1% of Orientals) are classified as poor metabolizers. Among the rest (extensive metabolizers), enzyme activity is highly variable, from extremely high in ultrarapid metabolizers, to markedly reduced in intermediate metabolizers. The CYP2D6 gene is highly polymorphic, with more than 70 allelic variants described so far. Of these, more than 15 encode an inactive or no enzyme at all. Others encode enzyme with reduced, "normal" or increased enzyme activity. The CYP2D6 gene shows marked interethnic variability, with interpopulation differences in allele frequency and existence of "population-specific" allelic variants, for instance among Orientals and Black Africans. The CYP2D6 enzyme catalyses the metabolism of a large number of clinically important drugs including antidepressants, neuroleptics, some antiarrhythmics, lipophilic beta-adrenoceptor blockers and opioids. The present-day knowledge on the influence of the genetic variability in CYP2D6 on the clinical pharmacokinetics and therapeutic effects/adverse effects of psychotropic drugs is reviewed.

499 citations


Cited by
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Journal ArticleDOI
30 Jul 1982-Science
TL;DR: Biochemical, electrophysiological, and pharmacological evidence supporting a role for cholinergic dysfunction in age-related memory disturbances is critically reviewed and an attempt has been made to identify pseudoissues, resolve certain controversies, and clarify misconceptions that have occurred in the literature.
Abstract: Biochemical, electrophysiological, and pharmacological evidence supporting a role for cholinergic dysfunction in age-related memory disturbances is critically reviewed. An attempt has been made to identify pseudoissues, resolve certain controversies, and clarify misconceptions that have occurred in the literature. Significant cholinergic dysfunctions occur in the aged and demented central nervous system, relationships between these changes and loss of memory exist, similar memory deficits can be artificially induced by blocking cholinergic mechanisms in young subjects, and under certain tightly controlled conditions reliable memory improvements in aged subjects can be achieved after cholinergic stimulation. Conventional attempts to reduce memory impairments in clinical trials hav not been therapeutically successful, however. Possible explanations for these disappointments are given and directions for future laboratory and clinical studies are suggested.

5,318 citations

Journal ArticleDOI
21 Jul 1979-BMJ
TL;DR: It is suggested that if assessment of overdoses were left to house doctors there would be an increase in admissions to psychiatric units, outpatients, and referrals to social services, but for house doctors to assess overdoses would provide no economy for the psychiatric or social services.
Abstract: admission. This proportion could already be greater in some parts of the country and may increase if referrals of cases of self-poisoning increase faster than the facilities for their assessment and management. The provision of social work and psychiatric expertise in casualty departments may be one means of preventing unnecessary medical admissions without risk to the patients. Dr Blake's and Dr Bramble's figures do not demonstrate, however, that any advantage would attach to medical teams taking over assessment from psychiatrists except that, by implication, assessments would be completed sooner by staff working on the ward full time. What the figures actually suggest is that if assessment of overdoses were left to house doctors there would be an increase in admissions to psychiatric units (by 19°U), outpatients (by 5O°'), and referrals to social services (by 140o). So for house doctors to assess overdoses would provide no economy for the psychiatric or social services. The study does not tell us what the consequences would have been for the six patients who the psychiatrists would have admitted but to whom the house doctors would have offered outpatient appointments. E J SALTER

4,497 citations

Journal ArticleDOI
TL;DR: Recent progress on drug metabolism activity profiles, interindividual variability and regulation of expression, and the functional and clinical impact of genetic variation in drug metabolizing P450s are reviewed.

2,832 citations

Journal ArticleDOI
TL;DR: This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori, which represents a key factor in the etiology of various gastrointestinal diseases.
Abstract: Helicobacter pylori is the first formally recognized bacterial carcinogen and is one of the most successful human pathogens, as over half of the world's population is colonized with this gram-negative bacterium. Unless treated, colonization usually persists lifelong. H. pylori infection represents a key factor in the etiology of various gastrointestinal diseases, ranging from chronic active gastritis without clinical symptoms to peptic ulceration, gastric adenocarcinoma, and gastric mucosa-associated lymphoid tissue lymphoma. Disease outcome is the result of the complex interplay between the host and the bacterium. Host immune gene polymorphisms and gastric acid secretion largely determine the bacterium's ability to colonize a specific gastric niche. Bacterial virulence factors such as the cytotoxin-associated gene pathogenicity island-encoded protein CagA and the vacuolating cytotoxin VacA aid in this colonization of the gastric mucosa and subsequently seem to modulate the host's immune system. This review focuses on the microbiological, clinical, immunological, and biochemical aspects of the pathogenesis of H. pylori.

2,246 citations