Biomedical subjects
Publications and source records attributed to T Thomsen.
We surveyed 297 patients with Parkinson disease (PD) with systematic screens and rigorous definitional criteria. Pathologic hypersexuality lifetime prevalence was 2.4%. Compulsive shopping was 0.7%. Combined with our pathologic gambling data, the lifetime prevalence of these behaviors was 6.1% and increases to 13.7% in patients on dopamine agonists.
Pulmonary surfactant protein A (SP-A) is an oligomeric collectin that recognizes lipid and carbohydrate moieties present on broad range of micro-organisms, and mediates microbial lysis and clearance. SP-A also modulates multiple immune-related functions including cytokine production and chemotaxis for phagocytes. Here we describe the molecular interaction between the extracellular matrix protein microfibril-associated protein 4 (MFAP4) and SP-A. MFAP4 is a collagen-binding molecule containing a C-terminal fibrinogen-like domain and a N-terminal located integrin-binding motif. We produced recombinant MFAP4 with a molecular mass of 36 and 66 kDa in the reduced and unreduced states respectively. Gel filtration chromatography and chemical crosslinking showed that MFAP4 forms oligomers of four dimers. We demonstrated calcium-dependent binding between MFAP4 and human SP-A1 and SP-A2. No binding was seen to recombinant SP-A composed of the neck region and carbohydrate recognition domain of SP-A indicating that the interaction between MFAP4 and SP-A is mediated via the collagen domain of SP-A. Monoclonal antibodies directed against MFAP4 and SP-A were used for immunohistochemical analysis, which demonstrates that the two molecules colocalize both on the elastic fibres in the interalveolar septum and in elastic lamina of pulmonary arteries of chronically inflamed lung tissue. We conclude, that MFAP4 interacts with SP-A via the collagen region in vitro, and that MFAP4 and SP-A colocates in different lung compartments indicating that the interaction may be operative in vivo.
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AIMS: The SCORE project was initiated to develop a risk scoring system for use in the clinical management of cardiovascular risk in European clinical practice. METHODS AND RESULTS: The project assembled a pool of datasets from 12 European cohort studies, mainly carried out in general population settings. There were 20,5178 persons (88,080 women and 11,7098 men) representing 2.7 million person years of follow-up. There were 7934 cardiovascular deaths, of which 5652 were deaths from coronary heart disease. Ten-year risk of fatal cardiovascular disease was calculated using a Weibull model in which age was used as a measure of exposure time to risk rather than as a risk factor. Separate estimation equations were calculated for coronary heart disease and for non-coronary cardiovascular disease. These were calculated for high-risk and low-risk regions of Europe. Two parallel estimation models were developed, one based on total cholesterol and the other on total cholesterol/HDL cholesterol ratio. The risk estimations are displayed graphically in simple risk charts. Predictive value of the risk charts was examined by applying them to persons aged 45-64; areas under ROC curves ranged from 0.71 to 0.84. CONCLUSIONS: The SCORE risk estimation system offers direct estimation of total fatal cardiovascular risk in a format suited to the constraints of clinical practice.
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The present study investigated changes in neuronal activation with fMRI related to Honig's model of working memory, which is much less studied compared with other working memory models. In contrast to other studies which have applied recognition procedures, the primary aim with the present study was to examine brain activation when subjects had to continuously recall and forget items held in working memory. The results showed that the mid-ventrolateral frontal cortex was particularly activated in the left hemisphere, whereas the mid-dorsolateral frontal cortex was particularly activated in the right hemisphere during execution of the working memory task. The findings are discussed in relation to process- and domain-specific accounts of working memory.
The purpose of the present study was to investigate differences in brain activation with functional magnetic resonance imaging (fMRI) during imagery of painful and non-painful 'finger movements' and 'hand positioning' in a subject with an amputated arm. The subject was a right-handed man in his mid-thirties who lost his right arm just above the elbow in a car-train accident. MRI was performed with a 1.5 T Siemens Vision Plus scanner. The basic design involved four conditions: imagining 'painful finger movements', 'non-painful finger movements', 'painful hand positioning', 'non-painful hand positioning'. Imagery of finger movements uniquely activated the contralateral primary motor cortex which contains the classic 'hand area'. The lateral part of the anterior cerebellar lobe was also activated during imagery of finger movements. Imagery of pain uniquely activated the somatosensory area, and areas in the left insula and bilaterally in the ventral posterior lateral nucleus of the thalamus. It is suggested that the insula and thalamus may involve neuronal pathways that are critical for mental processing of pain-related experiences, which may relate to a better understanding of the neurobiology of phantom limb pain.
The present paper reviews data from two previous studies in our laboratory, as well as some additional new data, on the neuronal representation of movement and pain imagery in a subject with an amputated right arm. The subject imagined painful and non-painful finger movements in the amputated stump while being in a MRI scanner, acquiring EPI-images for fMRI analysis. In Study I (Ersland et al., 1996) the Subject alternated tapping with his intact left hand fingers and imagining "tapping" with the fingers of his amputated right arm. The results showed increased neuronal activation in the right motor cortex (precentral gyrus) when tapping with the fingers of the left hand, and a corresponding activation in the left motor cortex when imagining tapping with the fingers of the amputated right arm. Finger tappings of the intact left hand fingers also resulted in a larger activated precentral area than imagery "finger tapping" of the amputated right arm fingers. In Study II (Rosen et al., 2001 in press) the same subject imagining painful and pleasurable finger movements, and still positions of the fingers of the amputated arm. The results showed larger activations over the motor cortex for movement imagining versus imagining the hand being in a still position, and larger activations over the sensory cortex when imagining painful experiences. It can therefore be concluded that not only does imagery activate the same motor areas as real finger movements, but also that adding instructions of pain together with imaging moving the fingers intensified the activation compared with adding instructions about non-painful experiences. From these studies, it is clear that areas activated during actual motor execution to a large extent also are activated during mental imagery of the same motor commands. In this respect the present studies add to studies of visual imagery that have shown a similar correspondence in activation between actual object perception and imagery of the same object.
This study was undertaken to examine whether prostaglandin (PG) inhibition with indomethacin interferes with angiotensin II receptor blockade (losartan) during treatment for arterial hypertension. In a double-blind crossover design 10 patients with essential arterial hypertension and treated with losartan were randomized to supplementary treatment with indomethacin or placebo for 1 week, with a 2-week washout period interposed. At the end of each treatment period the following examinations were performed, preceded by 4 days on sodium-fixed diet: 24-h blood pressure (BP), 24-h sodium excretion (UNaV), supine BP, glomerular filtration rate (GFR), renal resistive index (RRI), extracellular fluid volume (ECV), sodium clearance (Cl(Na)), body weight, peripheral blood flow (PBF), and plasma concentrations of aldosterone, renin (PRC), and atrial natriuretic peptide (ANP). Indomethacin did not change BP. Indomethacin increased weight (P < .05) and ECV (P < .05). A nonsignificant decrease in UNaV was seen after indomethacin, as in 24-h Cl(Na). Conversely, in the laboratory in the supine position Cl(Na) increased after indomethacin (P = .05). Indomethacin increased plasma ANP (P < .01). No changes were observed in GFR, RRI, PBF, PRC, or plasma aldosterone. Thus indomethacin did not attenuate the antihypertensive effect of losartan, neither was peripheral blood flow affected. Indomethacin caused sodium retention in the nonresting situation, which was not counterbalanced by the increased Cl(Na) in the resting supine position. The observed changes during prostaglandin (PG) inhibition seem most likely due to lack of PG "protection" of renal function, when the sympathetic nervous system is activated throughout the day.
BACKGROUND AND OBJECTIVES: Omeprazole is an inducer of human cytochrome P450 1A (CYP1A) enzymes, but shows inhibitory effects on CYP2C19 and CYP3A4. In this study, a potential inhibitory effect of omeprazole on caffeine metabolism, a validated CYP1A2 marker, was examined. METHODS: A randomized, balanced crossover single-dose study was conducted in 16 healthy volunteers comprising 12 extensive (EM) and 4 poor metabolizers (PM) for CYP2C19. All volunteers received a 40 mg omeprazole dose or placebo 0.5 h prior to caffeine 3 mg/kg body weight. Six EMs were re-tested with 80 mg of omeprazole. In vitro, effects of omeprazole on caffeine N3-demethylation were determined in human liver microsomes. RESULTS: In vivo, non-parametric point estimates (90% confidence intervals) for the ratios of caffeine pharmacokinetics with/without co-administration of the 40 mg omeprazole dose were: AUC 1.08 (1.04 - 1.13), MRT 1.09 (0.99 - 1.19), and plasma ratio of paraxanthine/caffeine 6 h post-dose 0.91 (0.80 - 1.00). Inhibition of caffeine N3-demethylation by omeprazole was slightly more pronounced in PM than in EM of CYP2C19. Estimates for the 80 mg omeprazole dose were: AUC 1.12 (1.05 -1.18), MRT 1.18 (1.07 - 1.30), and paraxanthine/caffeine ratio 0.83 (0.74 -0.94). In vitro, omeprazole was mainly a competitive CYP1A2 inhibitor with K(i) values of around 150 microM. CONCLUSIONS: Omeprazole exerts a concentration-dependent inhibition of CYP1A2 activity in man. However, even after single oral doses up to 80 mg, this effect is weak and without clinical relevance.
Galanthamine proved effective in symptomatic treatment of senile dementia of Alzheimer's type. The aim of this study was to elucidate the metabolism of galanthamine. Two novel metabolites of galanthamine have been isolated from the urine of eight young men after single doses of 10-15 mg. Some 19.8% of the doses were excreted as O-demethylgalanthamine glucuronide, 5% as N-demethylgalanthamine, 25.1% as galanthamine, and 0.8% as epigalanthamine. After coadministration of quinidine hydrogen sulfate, which inhibits cytochrome P450 2D6 (CYP2D6) selectively, O-demethylgalanthamine glucuronide was highly diminished in urine. In vitro, human liver microsomes metabolized galanthamine to O-demethylgalanthamine with Vmax 5.2 nmol/mg protein/h and Km 187 microM. Ki of quinidine to inhibit O-demethylation was 28 nM. To inhibit cholinesterases, O-demethylgalanthamine was 10-fold more selective for acetylcholinesterase (AChE) versus butyrylcholinesterase (BuChE) than galanthamine. After glucuronidation, O-demethylgalanthamine failed to inhibit AChE and BuChE. N-Demethylgalanthamine inhibited cholinesterases less potently than galanthamine.
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The Nordic Network in Preventive Cardiology (NNPC), a new forum intended to promote collaboration between the Nordic countries in the epidemiology and prevention of cardiovascular disease, was founded in November 1996 at a meeting of 30 representatives from nine Nordic cardiovascular centres. The plans include among other things the creation of a data base of population and intervention studies, to organize seminars and workshops, to standardize measuring techniques, questionnaires and analysing methods. The NNPC has established contract with the European Society of Cardiology and various centres in the Nordic countries.
AIMS: The aim of this study was to determine the potential influence of renal impairment on the pharmacokinetics of temocapril and its pharmacologically active diacid metabolite, temocaprilat. METHODS: Non-compartmental pharmacokinetics were assessed in four groups of hypertensive patients (n=8 per group, four investigational centres) with normal (creatinine clearance determined via 24 h urine sampling, CL[CR], > or = 60 ml min-1) and impaired renal function (CL[CR] 40-59, 20-39, < 20 ml min-1) after 14 once daily oral doses of 10 mg temocapril hydrochloride. RESULTS: For temocapril, there were no statistically significant differences in median tmax or mean Cmax, AUC(SS), t1/2,Z, CL/F between the four groups. Renal clearance, CL(R), for temocapril showed a linear decreasing trend with decreasing CL(CR) [mean (s.d.): 32.2 (10.7) to 3.7 (3.0) ml min-1]. Steady-state for temocaprilat was reached on day 5. For temocaprilat, no statistically significant differences in mean Cmax or median tma were detected. With decreasing mean CL(CR), mean AUC(SS) for temocaprilat increased statistically significantly although only 2.4-fold [mean (s.d.): 2115 (565) to 4989 (2338) ng ml-1 h] and t1/2,Z was prolonged [mean (s.d.): 15.2 (1.2) to 20.0 (7.5) h]. CL(R) for temocaprilat showed a linear decreasing trend with decreasing CL(CR) [mean (s.d.): 20.2 (4.3) to 3.0 (1.8) ml min-1]. CONCLUSIONS: These results indicate that impaired renal function has only a limited effect on the pharmacokinetics of temocapril and its active metabolite, temocaprilat. This may be attributed to the dual, i.e. renal and biliary, elimination pathway of the drug.
The action of galanthamine (GAL), a cholinesterase inhibiting substance, on resting EEG and on flash visual evoked potentials (VEPs) was tested in 9 healthy subjects. Alpha power was increased significantly in 4 of 8 subjects after the infusion of 10 mg, which provided a median inhibition of 47% of acetylcholinesterase in erythrocytes. Mean alpha frequency and peak alpha frequency decreased significantly in 5 of the 8 subjects by 0.22-0.98 Hz. Alpha power increase and alpha frequency decrease were not accompanied by changes in theta power. The amplitudes of the late components of the flash VEP were increased in 8 of 9 subjects receiving doses of 10-35 mg of GAL, while the early components remained unaffected. Increase of late VEP components was significantly correlated with the strength of cholinesterase inhibition. The synchronizing effect of GAL in these healthy volunteers obviously contrasts with the known desynchronizing effect of physostigmine in animal experiments.
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Galanthamine was determined in plasma and tissue extracts of mice, after the application of 4, 6 and 8 mg/kg (i.v.), by reverse phase HPLC, with fluorescence detection. A biexponential decline of concentrations in plasma, with a terminal half-life of 43.3 min, was observed after the dose of 4 mg/kg. The volume of distribution (Vss) of 2.17 l/kg was similar to that found in other species, including man. Metabolism to the inactive diastereomer, epigalanthamine, was very limited. There was a rapid accumulation of galanthamine in tissues, which was most pronounced in the kidney (10-fold compared to plasma) and liver (5-fold). In brain, accumulation was similar to other parenchymatous organs (diaphragm, lung) and amounted to 2.10-fold. Red blood cells showed a concentration 1.34-fold greater than plasma. The accumulation of galanthamine in tissue, with the exception of liver and kidney, can be explained by passive distribution according to differences in pH, between intra- and extracellular compartments. Extraction of galanthamine from blood to brain tissue was complete, indicated by a clearance in the range of cerebral blood flow (1.05 ml min-1 g-1). The concentration-time course of galanthamine in brain tissue was parallel to that in plasma during the terminal elimination phase. Measurement of inhibition of acetylcholinesterase (AChE) in the same samples from brain revealed a maximum apparent inhibition of 43% in the homogenate of brain (1:4 w/v in phosphate buffer, 4 mg/kg, 5 min after injection).(ABSTRACT TRUNCATED AT 250 WORDS)