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Biomedical subjects

M Svensson

Publications and source records attributed to M Svensson.

At least 163 records · Page 9Linked to original sources
PubMed1987

The role of prerotation of the trunk in axial twisting efforts.

The myoelectric activity of selected trunk muscles was recorded during the development of controlled isometric axial torques. Muscle activity was measured bilaterally over the erector spinae, the rectus abdominus, the oblique external and the oblique internal abdominal muscles at the L3 level. Subjects first applied graded isometric torque efforts over a 10 second ramp up to maximum voluntary contraction with the trunk in neutral rotation. They then repeated the effort with the trunk twisted to the left and right. The largest electromyographic activities were found in the agonistic oblique muscles, but considerable antagonistic activity was present also. While the activity of the internal oblique and rectus were bilaterally similar in symmetric standing a difference occurred between the two sides when the trunk was twisted to the right or left. Axial prerotation of the trunk by 30 degrees in the direction of torque development marginally decreased the maximal developed torque, whereas prerotation in the opposite direction increased the developed torque.

Abdominal Muscles↗
PubMed1987

Radionuclide left ventricular volume determination. Influence of scattered radiation and surrounding activity.

Radionuclide measurements of left ventricular volumes, ejection fractions and stroke volumes were performed by an equilibrium technique in nine patients using left anterior oblique projection and individual depth correction. Phantom studies were made in order to evaluate attenuation and scattering of the radiation. It was found that a simple depth correction factor, k(d) = e mu d, can be used under certain conditions. However, the determination of left ventricular volume by radionuclide techniques is not a truly absolute method. The depth correction factor to be used is dependent on the condition of measuring and evaluation, for instance how the region of interest for the left ventricle is selected. Therefore, this method should be carefully standardized, evaluated and compared to other techniques. Stroke volume measured by radionuclide and dye-dilution technique showed a correlation coefficient of 0.76 (nine patients) at rest and 0.77 (seven patients) at work. This method can be easily performed during routine ejection fraction determination and can thus be useful in clinical studies.

Adult↗
PubMed1987

The response of the seated human to sinusoidal vibration and impact.

Low back pain has been shown to occur more frequently among vehicle drivers than in representative control groups. Thus the response of the human to vibration and impact is of interest. This study investigated the response of the spine to both impact and sinusoidal excitation in either a relaxed or erect seated posture. The sinusoidal testing apparatus used was a resonating system consisting of two parallel wooden beams, simply supported, and the impact testing apparatus a bearing-guided, spring-suspended platform, struck from below. Ten subjects (5 males, 5 females) were evaluated using both methods. Transfer functions were compared at 2-4 Hz, 4-8 Hz and 8-16 Hz intervals using a sign test. Although in 24 comparisons of either test method (vibration or impact) or posture (erect or relaxed) where eleven showed differences significant at the p less than .05 level, only 2 out of 24 comparisons were the differences distinct enough to be significant (at the p less than .01 level). Both of these latter differences were due to test method while the subjects were sitting erect. In those instances where there were no significant differences due to test method, the impact method may be a viable replacement for the vibration test method. Where the levels of significance are higher (p less than .01 or p less than .05), further study of the magnitude of the differences is indicated and may reveal further insight into the seated individual as a system.

Adolescent↗
PubMed1986

Electromyographic studies of the lumbar trunk musculature during the development of axial torques.

The myoelectric activity of selected trunk muscles at the L3 level was studied during the development of a controlled isometric axial torque. Muscle activity was recorded with surface electrodes bilaterally over the erector spinae muscles, the rectus abdominus, the obliques externus, and the obliques internus. Subjects applied graded isometric axial torque efforts with the addition of a Valsalva. The largest myoelectric activities were recorded over the obliques externus and internus. The side of the muscle developing the torque did show the greatest myoelectric activity, but considerable antagonistic activity was also present. Neither the rectus abdominus nor the internal oblique muscles showed any difference from side to side. The calculated forces in the rectus abdominus and the erectores spinae were high, suggesting that a considerable amount of the muscle contraction was used to control the posture. A Valsalva did not decrease myoelectric activity, but did increase the torque developed.

Abdominal Muscles↗
PubMed1986

Mounting of the transducers in measurement of segmental motion of the spine.

A seated female subject was subjected to sinusoidal whole body vibration at 2, 4, 5 and 6 Hz. Accelerations were measured by accelerometers on pins screwed into the spinous process. The pins were also fitted with light emitting diodes (LED). The displacement of these LEDs were compared to LEDs attached directly to the skin. Substantial differences in measured displacements were noted between surface mounted LEDs and those mounted on pins rigidly attached to the skeleton. These differences were more marked further out from the center line.

Adult↗
PubMed1986

Monoclonal opsonic mouse antibodies specific for streptococcal IgG Fc-receptor.

Spleen cells from mice immunised with group-A type-M15 streptococci and boosted with purified IgG Fc-receptor (FcR) from this type were fused with Sp 2/0 mouse myeloma cells. The resulting hybridomas were screened by ELISA for antibody production. Two IgM-secreting cell lines were selected. The monoclonal antibodies and ascites fluids inhibited the binding of 125I-labelled human IgG and IgG Fc-fragments to group-A type-M15 streptococci. The monoclonal antibodies also displaced purified FcR towards the anode in electrophoresis. They opsonised group-A type M-15 streptococci for phagocytosis by human granulocytes in the presence of fresh human serum. It was concluded that FcR is important for group-A streptococcal virulence.

Animals↗
PubMed1983

Locomotor system disorders in diabetes mellitus. Increased prevalence of palmar flexortenosynovitis.

Diabetes mellitus (DM) may be accompanied by a variety of locomotor system disorders including several hand syndromes. It has been suggested that palmar flexortenosynovitis (FTS) might be included among these hand syndromes, but no conclusive data have been available. Furthermore, recent studies have indicated that FTS may be a clue to previously undiagnosed impaired glucose tolerance. In the present study the prevalence of FTS among diabetics without inflammatory rheumatic disease was 11% compared with less than 1% (p less than 0.001) in a reference group. Thus, FTS could be included among the locomotor system disorders which are associated with DM.

Adult↗
PubMed1982

Five new Gc variants detected by isoelectric focusing in agarose gel.

Five new genetically determined Gc variants were observed by isoelectric focusing. Seven rare variants 1A4, 1Cl, 1C3, 1C9, 1C11, 2A2, and 2A5 were also found in the material comprising Danish and Swedish paternity cases. All the variants were further analysed by electrophoresis in agarose gel. Two of the new variants had double bands of which the anodal one was susceptible to neuraminidase treatment (Gc 1C13 and 1C14). The three other new variants appeared as a single band, which was unaffected by neuraminidase treatment (Gc 2A9, 2C5, and 2C6). The Gc Ar variant originally detected by electrophoresis was reexamined by isoelectric focusing and named 2C4.

Adult↗
PubMed1981

Content of trans-octadecenoic acid in vegetarian and normal diets in Sweden, analyzed by the duplicate portion technique.

The intake of trans fatty acids by subjects adhering to the normal Swedish diet or to different vegetarian regimes was studied, using chemical analysis of duplicate portions. Trans-octadecenoic acid was 5.0, 3.9, and 1.8% of dietary fatty acid in the normal, lactovegetarian, and vegan diets, respectively, corresponding to 2.0, 1.3, and 0.5% of energy intake. The results are related to the content of trans-octadecenoic acid in some edible fats.

Butter↗
PubMed1977

Enhancement of [3H-methyl]thymidine incorporation and replication of rat chondrocytes grown in tissue culture by plasma, tissue extracts and vasopressin.

A pituitary mitogenic peptide, which stimulates cellular replication of a variety of cells maintained in tissue culture, has been identified by other investigators. To study this mitogenic substance, we developed an assay to measure mitogenic substances utilizing fetal rat chondrocytes grown in monolayer culture. Mitogenic activity of added test substances was determined by [3H-methyl]thymidine incorporation into trichloroacetic acid insoluble cell products and increase in total cell number after 24 h exposure. Extracts of whole pituitary glands were more potent in stimulating these cellular indices than either those of liver or muscle, confirming that the chondrocytes are sensitive to the described mitogen. Identically prepared extracts of either anterior or posterior pituitary lobes were mitogenic indicating the presence of two or more mitogenic substances in crude pituitary extracts. Synthetic lysine vasopressin and a beef pitressin concentrate stimulated thymidine incorporation into chondrocytes in the absence of calf serum and this effect was additive to that of calf serum, suggesting that the mitogenic substance of posterior pituitary extracts was vasopressin. The maximum effective dose of vasopressin leading to an increase in either thymidine incorporation or total cell number was between 100 to 500 pg/ml, and as little as 50 pg/ml of hormone elicited an increase in total cell number. The mitogenic effect of both vasopressin and calf serum on chondrocytes was partially inhibited by 1 X 10(-4)M N, O'dibutryl cyclic adenosine 3',5' monophosphate suggesting that cell division of chrondrocytes may be under tonic control by the andenylyl cyclase system. We conclude that vasopressin is a potent mitogen for chondrocytes maintained in tissue culture and its presence must be rigorously excluded in evaluating mitogenic activity of pituitary or serum concentrates.

Animals↗
PubMed1976

Formation of dry-heat resistant Bacillus subtilis var. niger spores as influenced by the composition of the sporulation medium.

Bacillus subtilis var. niger spores were produced on 20 different media. The spore yield from each medium and the dry-heat resistance at 160 C of the different spore populations were determined. The yield varied with a factor of 10(6) and the variation in D 160-value was about 10-fold (less than 20 S-190 S). A "synthetic" medium producing a high yield of spores with high dry-heat resistance was formulated. The concentrations of glucose, sucrose and calcium were found to be critical.

Bacillus subtilis↗
PubMedDate not supplied

Complement and clusterin in the injured nervous system.

Peripheral nerve injury and neuronal degeneration resulting from toxic ricin induce activation of the classical pathway of complement close to the injured motorneuron perikarya or sensory terminals. In contrast, degeneration of central myelinated fibers is not accompanied by complement expression. The main source of complement in peripheral nerve injury and toxic ricin degeneration appears to be microglia. Brain contusion is associated with complement activation. Some of the complement in this situation may derive from plasma, because the blood-brain barrier is disrupted. Clusterin expression is increased in astrocytes along with their activation in the vicinity of lesioned neurons. In addition, axotomized motorneurons show a marked clusterin upregulation. A relationship between clusterin and cell death is suggested by the prominent aggregation of clusterin in neuronal perikarya destroyed by the effects of toxic ricin, as well as by the neosynthesis of clusterin in apparently degenerating nonneuronal cells, presumed to be oligodendrocytes. Our findings indicate that the expression of complement and clusterin are prominent features of neural degeneration and regeneration, as it is in Alzheimer's disease brains as well. The nerve injury conditions described, therefore, offer attractive experimental models to elucidate the roles of these molecular components in neurodegenerative disorders, thereby providing useful insights into potentially new therapeutic approaches in these conditions.

Animals↗
PubMedDate not supplied

Antigen-presenting cells and anti-Salmonella immunity.

The present article summarizes studies aimed at addressing the role of antigen-presenting cell populations, particularly dendritic cells (DC), in the immune response to Salmonella typhimurium. Data from in vitro studies shed light on presentation of antigens expressed in Salmonella on major histocompatibility complex class I and class II molecules by infected DC and macrophages, and the activation state of DC following infection. Finally, data from in vivo studies addressing the role of DC and defined DC subsets during the host response to Salmonella using a murine infection model are discussed.

Animals↗
PubMedDate not supplied

Different profiles in specific IgE to rBet v 1 and rBet v 2 in patients allergic to birch pollen from six countries.

There are differences in IgE reactivity to rBet v 1 and rBet v 2 among allergic patients from the six countries studied. The complexity of the reactivity profile tends to be greater in individuals from the central/southern parts of Europe compared to Sweden and Finland. There is a good agreement between in vitro diagnosis with Pharmacia CAP System and Skin prick testing when using the same reagents, rBet v 1 and rBet v 2.

Allergens↗
PubMedDate not supplied

Isometric muscle strength and quantitative electromyography of back muscles in wrestlers and tennis players.

The isometric motor performance of the trunk muscles was studied in 10 male wrestlers and 9 male tennis players, all of whom were elite athletes. Isometric flexion, extension, and lateral bending were performed. The motor output, including fatigue, was studied by means of a load cell and using electromyography. The wrestlers were found to have symmetrical strength and were stronger in all measured directions, especially in side bending (flexion, 852 N; extension, 951 N; right and left side bending, 759 N and 744 N, respectively), than the tennis players and normal subjects of any published study. The development of fatigue in the erector spinae muscles, as evaluated by spectral analysis of the myoelectric signal, was not symmetrical and was significant bilaterally at the lumbar level and on the right side at the thoracic level. As expected, the tennis players had asymmetrical isometric strength. They were stronger in left side bending than right side bending (643 N compared with 557 N, P less than 0.01), and stronger in extension than flexion (835 N compared with 638 N, P less than 0.01). The development of fatigue in the erector spinae muscles was significant bilaterally at the lumbar level and on the left side at the thoracic level. The development of fatigue in the tennis players was less than that of the wrestlers except for the left thoracic measurement site. Our conclusions are that tennis players appear to be relatively weak in trunk flexion. The wrestlers displayed a development of fatigue that was asymmetrical and was of nearly the same degree as the tennis players, but on the opposite side.

Adult↗