Showing papers by "Seppo Koskinen published in 1993"

Scoring of patellofemoral disorders

Abstract: A new questionnaire was used to evaluate subjective symptoms and functional limitations in patellofemoral disorders. The questionnaire was completed independently by four groups of female subjects: controls (N = 17), and subjects with anterior knee pain (N = 16), patellar subluxation (N = 16), and patellar dislocation (N = 19). The questionnaire mean scores for the groups were 100, 83, 68, and 62 points, respectively (p < 0.0001). The items dealing with abnormal painful patellar movements (subluxations) (p < 0.0001), limp (p < 0.0001), pain (p < 0.0001), running (p < 0.0001), climbing stairs (p < 0.0001), and prolonged sitting with the knees flexed (p < 0.0001) differentiated the study groups most clearly. We recommend that these questions be asked when taking a standardized clinical history of an anterior knee pain patient. We also analyzed lateral patellar tilt and displacement by magnetic resonance imaging (MRI) in 28 subjects with patellar subluxation or dislocation. Low questionnaire sum score correlated best with increased lateral patellar tilt measured during quadriceps contraction in 0 degree knee flexion. It seems that a tendency to lateral patellar tilt during quadriceps contraction causes anterior knee pain and can be imaged in knee extension when the patella is not fully supported by femoral condyles.

Magnetic resonance imaging of patellofemoral relationships.

Abstract: Patellofemoral relationships were analyzed in 11 patients (13 knees) with patellar dislocation and 15 asymptomatic subjects (15 knees) at 0 degree and 20 degrees of flexion. The measurements were made from five consecutive axial images through the patellofemoral joint. The six indices measured were lateral patellar tilt (LPT), lateral patellofemoral angle (LPA), lateral patellar displacement (LPD), patella-lateral condyle index (L/PW), congruence angle (CA), and sulcus angle (SA). The reproducibility of the method was evaluated. The difference between the two study groups was more evident at 0 degree than at 20 degrees of knee flexion. Significant differences were noted between measurements made at different levels of the joint, particularly in the controls. Isometric contraction of the quadriceps muscle lateralized and tilted the patella slightly in both groups. L/PW with and without quadriceps muscle contraction, and LPA with reference to the anterior condyles differentiated between the two study groups most clearly. LPT and LPA with reference to the anterior condyles differentiated the study groups better than LPT and LPA with reference to the posterior condyles. The reproducibility was good except for inter-observer comparison of CA and SA. The use of an imaging plane selected at the midpoint of the patellar articular cartilage increases the sensitivity of the measurements, since it takes into account both the height of the patella and the tendency towards lateralization. These results indicate that patellar tilt is best measured with the LPA index and patellar lateralization with the L/PW index at 0 degree knee flexion. This study should always include isometric contraction of the quadriceps muscle.

Reduced turnover of dopamine and 5-hydroxytryptamine in discrete dopaminergic, noradrenergic and serotonergic rat brain areas after acutely administered medetomidine, a selective α2-adrenoceptor agonist

Abstract: Monoamine metabolism and turnover were investigated in discrete doparninergic, noradrenergic and serotonergic brain areas in the rat after acute administration of the selective α2-adrenoceptor agonist, medetomidine. Medetomidine (3, 30 and 100 μg/kg subcutaneously) was given 90 min. before decapitation and discrete brain nuclei were punched from frozen brain slices for the analysis of concentrations of noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA). In a separate experiment, the accumulation of 3,4-dihydroxyphenylalanine (DOPA) and 5-hydroxytryptophan (5-HTP) was measured after inhibition of L-aromatic amino acid decarboxylase by NSD 1015: medetomidine (3, 10 and 100 μg/kg subcutaneously) was given 60 min. before NSD 1015 (100 mg/kg intraperitoneally), and the rates of DOPA and 5-HTP accumulation were determined over 30 min. Finally, the antagonistic effect of idazoxan (1 mg/kg subcutaneously), a selective α2-adrenoceptor blocking agent, on the medetomidine-induced changes in monoamine metabolism was investigated. Medetomidine markedly decreased the metabolism and turnover of DA in the nucleus caudatus, but not in the nucleus accumbens or substantia nigra. In all dopaminergic areas, the turnover of 5-HT was markedly inhibited by medetomidine. These effects were significantly counteracted by idazoxan pretreatment demonstrating the α2-receptor mediated action of medetomidine. The turnover of 5-HT was also reduced by medetomidine in the nucleus raphe dorsalis, the A1-Cl area, locus coeruleus, nucleus tractus solitarius and the A5 area. The accumulation of DOPA was markedly inhibited in the A1-C1 area, nucleus tractus solitarius and nucleus raphe dorsalis, but not in locus coeruleus. In these brain stem areas the accumulation of DOPA mainly takes place in noradrenergic neurones and thus reflects the in vivo rate of synthesis of NA. It is concluded that in spite of the proven α2-adrenoceptor selectivity and specificity of medetomidine it has marked effects on the metabolism and turnover of other neurotransmitters in addition to NA. This is in agreement with the wide distribution of α2-adrenoceptors in the central nervous system. Furthermore, it suggests that important interactions take place between different monoaminergic neurones, reducing the in vivo selectivity of drug actions.

Exercise-induced changes in magnetization transfer contrast of muscles

Abstract: Magnetization transfer contrast (MTC) technique provides a new type of contrast in MR imaging. The MTC method is based on the interaction between the spins of free protons and those with restricted motion. Exercise-induced changes in signal intensity and MTC were measured in the forearm muscles of 10 volunteers at 0.1 T. There was 26% increase in signal intensity of active flexor muscles after exercise when imaged with ordinary gradient echo sequence. Despite this marked intensity increase, the postexercise values of MTC did not differ from the preexercise ones.

Low-Field Strength Magnetization Transfer Contrast Imaging of the Patellar Cartilage:

Abstract: The time-dependent saturation transfer (TDST) method was applied at 0.1 T in order to evaluate the magnetization transfer contrast (MTC) of the patellar cartilage in vivo. Nine knees were examined. The MTC image of the knee is also demonstrated. The MTC of 63% of the patellar cartilage was attained. Magnetization transfer MR imaging may be of additional help in the evaluation of cartilage disorders at low-field MR imaging.