Biomedical subjects

Johan Ahlner

Publications and source records attributed to Johan Ahlner.

24 records · Page 2Linked to original sources

PubMed2002

Disposition of venlafaxine enantiomers in rats with hepatic encephalopathy after chronic drug treatment.

Portacaval shunted (PCS) rats, a model of hepatic encephalopathy, and control animals were administered racemic venlafaxine for 14 days (10 mg/kg). The levels of the S- and R-enantiomers and the S/R-enantiomer ratios of venlafaxine and its metabolites were assessed by an enantiomer-selective chromatographic assay in serum, brain parenchyma, and brain dialysate of both groups. Higher levels of the S- and R-enantiomers of venlafaxine were found in serum and brain of PCS vs. normal rats (median values of S- and R-venlafaxine in serum: 290 and 201 nM in PCS; 97 and 66 nM in normal rats; median values of S- and R-venlafaxine in cortex: 956 and 939 nM in PCS; 357 and 318 nM in normal rats). Interestingly, similar S/R-venlafaxine ratios were observed in PCS and normal rats both in serum (S/R = 1.4) and brain compartments (S/R = l.0-1.1). These findings may have clinical relevance for the safety of venlafaxine in chronic hepatic encephalopathy.

Animals↗

PubMed2002

Asthma nurse practice improves outcomes and reduces costs in primary health care.

OBJECTIVE: The aim of this study was to elucidate the care of patients with asthma in primary health care from medical, patient self-management, health, quality of life, and health economic perspectives. METHODS: Asthma nurse practice (ANP), an alternative asthma self-management strategy, was compared with traditional asthma care in primary health care in southern Sweden regarding medical history, lifestyle, self-management, symptoms caused by asthma, effects on sick leave, state of health, quality of life and health care costs. The first part of the investigation comprised a retrospective study of a randomly selected sample of patient records of asthmatics (n=152). The second part, lasting 3 months, was prospective and included consecutive patients visits (n=347). RESULTS: The ANP approach showed better results in most of the evaluated outcomes such as asthma quality documentation and self-management and the number of asthma symptoms was significantly lower. From a health economic perspective the results were encouraging with respect to ANP. CONCLUSION: This alternative asthma strategy, ANP, improved asthma care in primary health care and resulted in economic advantages in the health care sector. However the result may only be generalized to other practices working with asthma nurses in the same way.

Adult↗

PubMed2002

Serum levels of citalopram and its main metabolites in adolescent patients treated in a naturalistic clinical setting.

The prescribing of selective serotonin reuptake inhibitors for adolescents is extensive despite the fact that there are few pharmacokinetic (PK), efficacy, safety, or tolerability studies on this group. This study reports the PK findings from two trials in adolescents treated with citalopram (CIT) in naturalistic clinical settings: one retrospective and one prospective. The aim of our study was to describe serum concentrations of CIT, desmethylcitalopram (DCIT), and didesmethylcitalopram (DDCIT) (trough values in steady state) in adolescents in relation to daily dose and clinical information obtained from therapeutic drug monitoring request forms. Altogether, 44 patients younger than 21 years were scrutinized using this combined open-label approach. The main findings were that (1) there was a pronounced interindividual variability of serum CIT, DCIT, and DDCIT concentrations in all doses prescribed, in agreement with previous studies on adults; on correcting for dose, the coefficient of variance was about 50% for CIT, DCIT, and DDCIT; (2) the transformation of CIT to DCIT and of DCIT to DDCIT was similar within the dose range 20 to 60 mg/day; (3) there was a difference between the sexes on comparing the dose-corrected concentrations of CIT and DCIT, with girls presenting significantly higher values than boys; and (4) there was a strong dose-serum concentration relationship in three identified subgroups of adolescents: (a) nonsmokers (CIT, r(2) = 0.71; DCIT, r(2) = 0.81), (b) girls not taking oral contraceptives (CIT, r(2) = 0.75; DCIT, r(2) = 0.71,), and (c) girls in the last 14 days of the menstrual cycle (CIT, r(2) = 0.68; DCIT, r(2) = 0.64). In summary, the present study tentatively supports influences of sex, oral contraceptives, and smoking habits on the disposition of CIT in younger patients. Hence, future studies on CIT should assess these parameters.

Adolescent↗

PubMed2002

No effect of chinese acupuncture on isocapnic hyperventilation with cold air in asthmatics, measured with impulse oscillometry.

The cost to society and the individual of treating asthma has been increasing in developed countries. This has given rise to studies of the efficacy of complementary treatments. The aim of this study was to evaluate the efficacy of traditional Chinese Acupuncture in patients with mild asthma. The method used for evaluation of efficacy was total airway resistance at 5Hz (R5) as measured by impulse oscillometry (IOS)--a forced oscillation technique, at baseline and after a bronchial challenge with voluntary isocapnic hyperventilation of cold air (IHCA). The study was a parallel group randomised placebo controlled trial with evaluator blinding. Twenty-seven asthmatics were recruited and 24 completed the study, 10 of them received acupuncture and 14 received a placebo treatment (mock-TENS). Treatment continued for 15 weeks, and efficacy was tested two weeks following the last treatment. Randomisation resulted in female over representation in the acupuncture group, but lung-function and bronchial responsiveness to IHCA were comparable in the two populations before the start of treatment (p>0.05 vs. p > 0.05). There were no statistically significant effects of the treatment before (p > 0.05) or after IHCA (p > 0.05) in either of the groups. The statistical power of the study to show a clinically relevant difference in bronchial responsiveness to IHCA after treatment was near 80%. We conclude that there were no significant effects of traditional Chinese Acupuncture on airway status in our patients with asthma.

Acupuncture Therapy↗

PubMedDate not supplied

A2 (N-benzylpiperazine) a new drug of abuse in Sweden.

N-Benzylpiperazine was tested in the beginning of the 1970s as a possible antidepressant drug. However, in both animal and human studies, it was shown to possess amphetamine-like properties, and any further studies were stopped. In a forensic autopsy case in 1999, we found a substance so far unknown to us in the chromatogram of our method used for amphetamines. We could swiftly identify this compound as N-benzylpiperazine because of information given to us by a newly formed network comprising, among others, customs and the police. Since then, we have found N-benzylpiperazine in several cases, among them 11 cases from a number of prisons.

Adult↗

PubMedDate not supplied

Postmortem redistribution of the enantiomers of citalopram and its metabolites: an experimental study in rats.

A rat model was used to study if postmortem redistribution of the S- and R-enantiomers of citalopram (CIT) and its metabolites demethylcitalopram (DCIT) and didemethylcitalopram (DDCIT) occurs after three different subcutaneous dosing procedures with racemic CIT. Two groups underwent chronic administration (20 mg/kg daily) using osmotic pumps. After 10 days, 1 of these groups received an acute-on-chronic drug challenge with a single injection of 100 mg/kg. The third group received the single 100 mg/kg dose only. Heart blood and brain samples were collected antemortem and 1, 3, or 24 h postmortem for enantioselective HPLC analysis. Increased postmortem blood drug and metabolite concentrations compared with corresponding antemortem concentrations were observed in all groups (p < 0.05 to p < 0.001). At 24 h after death, the ratios between postmortem and antemortem blood concentrations were around 3-4 for CIT as well as for the metabolites. In the brain, no major differences between antemortem and postmortem drug and metabolite concentrations were observed. The enantiomeric (S/R) concentrations ratios of CIT and metabolites in blood and brain were of similar magnitude before and after death. No differences between antemortem and postmortem parent drug-to-metabolite (P/M) ratios for CIT/DCIT in blood were observed. Finally, this animal model demonstrates that the S- and R-enantiomers of CIT and its metabolites were redistributed to the same extent postmortem.

Animals↗