| 1. |
- Karlsson, Roger, 1944-
(författare)
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Interference with biological rhythm : a novel approach to metabolic disorders in women
- 1992
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Women seem to be largely protected against certain ‘welfare disorders’ such as cardiovacular disease and osteoporosis, during their fertile years.The metabolic changes observed during women’s non-menstrual states, i.e. during pregnancy, after the menopause and during use of oral contraceptives, indicate the importance of sex steroids and an undisturbed biological rhythm. Treatment with monophasic, combined oral contraceptives constitutes a model for the non-cyclic state.Growth hormone (GH) is a pituitary hormone that has major metabolic effects. The pattern of GH exposure to the target organ is of vital importance for the effects and changes in rhythm could possibly induce metabolic changes.Growth hormome, cholecystokinin (CCK), osteocalcin and angiotensinogen were used as markers for metabolic effects and the concentrations in serum were recorded in women during non-menstrual states. The clinical material comprised a total of 60 women: 18 healthy non-pregnant, 25 pregnant, one lactating woman and 16 postmenopausal women. Using a portable pump and a non-thrombogenic venous catheter, blood samples could be collected at 30-min intervals during 24-h periods. Furthermore, the effects of estrogen and GH in the regulation of angiotensinogen were investigated in an experimental model in the rat.Oral contraceptives were found to alter the secretion of GH towards a pattern of lower and more frequent peaks, though the total amount secreted during 24 h was unchanged. Oral contraceptives seem to induce a suppression of the 24-h concentrations of CCK, which may be important with respect to weight gain in some women. Osteocalcin in serum display a significant circadian variation. This emphasizes the need for careful timing of single point measurements and the value of continuous blood sampling. Oral contraceptives may reduce osteocalcin serum concentrations. The long-term effects on bone are unknown. During late pregnancy osteocalcin levels are extremely low, which could indicate osteoblast inhibition and reduced bone turnover. The mode of GH administration is important for the plasma concentration of angiotensinogen in the non-pregnant rat. Estrogen effects on this protein may be mediated via a modification of GH secretion. Oral contraceptives not only increase angiotensinogen concentrations in serum but also markedly enhance their variability. Further studies are needed to elucidate the relation between the individual pattern of angiotensinogen and hypertension.
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| 2. |
- Nilsson, Kenneth, 1948-
(författare)
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Radiation induced pneumonitis : clinical and experimental studies with special emphasis on the effect of smoking
- 1992
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bronchoalveolar lavage (BAL) is an established method providing diagnostic support and evaluation of disease activity in interstitial lung disease (ILD). The aims of the present investigation were 1) to study the inflammatory response in pneumonitis evoked by irradiation. 2) to evaluate how well lung tissue inflammation is reflected in BAL findings. 3) to study the effect of smoking on radiation-induced pneumonitis.BAL was performed in 21 patients (11 smokers, 10 non-smokers) who were treated for breast cancer, stage 1 (TjMaNq) by post-surgery irradiation to an accumulated target dose of 56 Gy. It was founa that irradiation induced an alveolitis in the non-smoking patient group while the smoking patients did not differ from their smoking controls. The alveolitis in non-smokers was characterized by an increase in lymphocytes, mast cells and elevated concentrations of hyaluronan (HA), and fibronectin (FN). Three of the non-smoking patients had chest X-ray infiltrates indicating the presence of pneumonitis.An animal experimental model for radiation-induced pneumonitis and fibrosis was established in rats, allowing comparative analysis of BAL fluid and morphology. In the rat model a divergence was noted between the differential cell counts in BAL and cells observed in the interstitial tissue, which was most notable for neutrophils (PMN) and mast cells whereas there was a good correlation between HA content in BAL and HA deposition in the lung tissue. A marked infiltration of intraseptally-located mast cells occurred during the pneumonitis-phase, and this increase was paralleled by a deposition of HA in the interstitial tissue. Histochemical fixation and staining properties of the mast cells revealed that the majority of these cells were of connective tissue mast cell type (CTMC). Compound 48/80, a mast cell secretagogue, significantly altered the HA content both in BAL and in lung tissue in the irradiated animals. Regular treatment throughout the whole experimental period induced depletion of mast cell granules and a decrease in HA deposition whereas 48/80 treatment during the pneumonitis phase enhanced HA deposition.A rat model with smoke exposure was developed, and the effect of cigarette smoke on radiation-induced inflammation was studied. Rats that smoked 3 weeks prior to irradiation and continued to smoke throughout the observation period (7 weeks) had a significantly reduced inflammatory response compared to irradiated non-smoking rats. The most prominent BAL findings in the smoke-exposed rats were a decrease in PMN, mast cells and a decrease in HA.In conclusion, irradiation induces an alveolitis characterized mainly by mononuclear cells. Mast cells seem to be of importance in the remodelling of the connective tissue in the radiation-induced inflammatory response. Hyaluronan is an important component in the early connective tissue response preceding later collagen deposition, and its interstitial deposition is very well reflected in BAL. Moreover, tobacco-smoke suppresses the radiation-induced inflammation with a decreased recruitment of effector cells including mast cells.
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| 3. |
- De Bruyn, H, et al.
(författare)
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A comparative study of the clinical efficacy of Screw Vent implants versus Brånemark fixtures, installed in a periodontal clinic.
- 1992
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Ingår i: Clinical Oral Implants Research. - 0905-7161 .- 1600-0501. ; 3:1, s. 32-41
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Tidskriftsartikel (refereegranskat)abstract
- The clinical success of 85 Screw Vent and 107 Brånemark implants, consecutively installed in a private periodontal clinic under the same conditions and by the same operator, is compared. Mobile implants were removed and considered as failures. Intra-oral radiographs were assessed for the presence of peri-implant radiolucencies and for analysis of bone loss after functional loading. 85 Screw Vent implants were installed in 31 patients. Of 23 implants installed in 9 mandibles, none failed after 16.8 (range 12-25) months of function. Of 62 Screw Vent implants installed in 23 maxillae, 6 failed at abutment connection, 1 failed after 2 months and 2 after 13 months of function. The absolute failure rate after 13.2 (range 6-24) months was 9/62. Mean loss of bone was 1.47 mm (-1.0- +4) after 12 months of functional loading. 107 Brånemark fixtures were installed in 25 patients. Of 51 fixtures inserted in 12 mandibles, none failed; of 56 fixtures installed in 13 maxillae 1 failed before and 2 failed during abutment connection. The absolute failure is 3/56. All remaining fixtures were immobile after loading. 13 fixtures were more than 6 months in function. Only short-term comparison between both systems is possible because the observation time is longer for the Screw Vent implants. In the 1st year, only 1 implant system was available to the periodontist. Short-term comparison reveals 11.3% versus 5.3% of cumulative failure after 6 months for the Screw Vent and Brånemark implants, respectively. The results indicate that clinical efficacy is as effectively obtained with Screw Vent as with Brånemark implants in the mandible. The outcome of treatment with Screw Vent implants in the maxilla seems less predictable.
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| 4. |
- Flygare, Lennart, et al.
(författare)
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Macroscopic and microscopic findings of areas with radiologic erosions in human temporomandibular joints
- 1992
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Ingår i: Acta Odontologica Scandinavica. - : Informa Healthcare. - 0001-6357 .- 1502-3850. ; 50:2, s. 91-100
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Tidskriftsartikel (refereegranskat)abstract
- The aim was to describe the macroscopic and microscopic findings of areas with radiologic erosions in the human temporomandibular joint. An autopsy material of 40 human joints, removed as blocks, was examined with tomography, and an erosion was found in 37 areas. A macroscopic and a microscopic examination focused on the presence of the calcified cartilage zone (CCZ) was performed in these areas. In the condyle 13 of 14 areas with a radiologic erosion showed denudation of bone macroscopically. Microscopically, these areas were covered by a thin fibrocellular tissue, and the CCZ was absent. In the temporal component, only 1 of the 23 areas showed bone exposure macroscopically. Microscopically, the soft tissue in these areas varied in thickness. The CCZ was missing in 13 of the 23 areas, even in some areas that appeared normal macroscopically and were microscopically covered by intact soft tissue. Thus, in areas with a radiologic erosion the macroscopic and microscopic appearance differed between the condyle and the temporal component. The nature of the findings is discussed.
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| 5. |
- Grankvist, O, et al.
(författare)
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Detection of nephropathia epidemica virus RNA in patient samples using a nested primer-based polymerase chain reaction
- 1992
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Ingår i: Journal of Infectious Diseases. - 1537-6613 .- 0022-1899. ; 165:5, s. 934-937
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Tidskriftsartikel (refereegranskat)abstract
- A nested primer-based polymerase chain reaction was constructed for the detection of Puumala virus RNA in patient samples. Puumala virus RNA was detected in cells from the urinary and the respiratory tracts and in peripheral blood mononuclear cells of patients with nephropathia epidemica. After inoculation with nephropathia epidemica patient material on Vero E6 cells and propagation for nine passages (4 months), Puumala virus RNA was detected at every passage. Hybridization under high-stringency conditions revealed that the overall nucleotide homology between the different patient isolates and the prototype strain (Puumala) is high. Using cDNA from Hallnas B1 strain as a probe, hybridization occurred only under low-stringency conditions.
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| 6. |
- Helminen, Heikki, et al.
(författare)
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Kuormituksen vaikutus nivelrustoon [The effects of loading on articular cartilage].
- 1992
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Ingår i: Duodecim. - : Duodecim. - 0012-7183 .- 2242-3281. ; 108:12, s. 1097-1107
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Forskningsöversikt (refereegranskat)abstract
- Nivelen kuormitus on tärkeimpiä nivelruston aineenvaihduntaan ja rakenteeseen vaikuttavia fysiologisia tekijöitä. Kohtuullinen rytminen kuormitus lisää nuoren ihmisen nivelruston proteoglykaanipitoisuutta. Tämän vaikutuksesta rusto jäykistyy ja kasvaa paksuutta. Hyvin voimakas kuormitus ei aiheuta tällaista positiivista vastetta. Toisaalta nivelkuormituksen puuttuminen pienentää ruston proteoglykaanipitoisuutta ja heikentää kimmo-ominaisuuksia. Nämä surkastumismuutokset ovat suurimmaksi osaksi–elleivät kokonaan–korjautuvia. Kohtuullisella nivelkuormituksella voidaan siis ylläpitää ja parantaa nivelruston ominaisuuksia. Pitkäaikaisen liikkumattomuuden jälkeen nivelrusto on heikompi kuin normaalisti ja voi vaurioitua niveltä voimakkaasti kuormitettaessa. Siksi nivelen kuormitusta pitää lisätä toipumisvaiheessa vähitellen.
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| 7. |
- Johansson, Roland S, et al.
(författare)
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Somatosensory control of precision grip during unpredictable pulling loads. I. Changes in load force amplitude.
- 1992
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Ingår i: Experimental Brain Research. - 0014-4819 .- 1432-1106. ; 89:1, s. 181-191
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Tidskriftsartikel (refereegranskat)abstract
- In manipulating 'passive' objects, for which the physical properties are stable and therefore predictable, information essential for the adaptation of the motor output to the properties of the current object is principally based on 'anticipatory parameter control' using sensorimotor memories, i.e., an internal representation of the object's properties based on previous manipulative experiences. Somatosensory afferent signals only intervene intermittently according to an 'event driven' control policy. The present study is the first in a series concerning the control of precision grip when manipulating 'active' objects that exert unpredictable forces which cannot be adequately represented in a sensorimotor memory. Consequently, the manipulation may be more reliant on a moment-to-moment sensory control. Subjects who were prevented from seeing the hand used the precision grip to restrain a manipulandum with two parallel grip surfaces attached to a force motor which produced distally directed (pulling) loads tangential to the finger tips. The trapezoidal load profiles consisted of a loading phase (4 N/s), plateau phase and an unloading phase (4 N/s) returning the load force to zero. Three force amplitudes were delivered in an unpredictable sequence; 1 N, 2 N and 4 N. In addition, trials with higher load rate (32 N/s) at a low amplitude (0.7 N), were superimposed on various background loads. The movement of the manipulandum, the load forces and grip forces (normal to the grip surfaces) were recorded at each finger. The grip force automatically changed with the load force during the loading and unloading phases. However, the grip responses were initiated after a brief delay. The response to the loading phase was characterized by an initial fast force increase termed the 'catch-up' response, which apparently compensated for the response delay--the grip force adequately matched the current load demands by the end of the catch-up response. In ramps with longer lasting loading phases (amplitude greater than or equal to 2 N) the catch-up response was followed by a 'tracking' response, during which the grip force increased in parallel with load force and maintained an approximately constant force ratio that prevented frictional slips. The grip force during the hold phase was linearly related to the load force, with an intercept close to the grip force used prior to the loading. Likewise, the grip force responses evoked by the fast loadings superimposed on existing loads followed the same linear relationship.(ABSTRACT TRUNCATED AT 400 WORDS)
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| 8. |
- Johansson, Roland S, et al.
(författare)
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Somatosensory control of precision grip during unpredictable pulling loads. II. Changes in load force rate.
- 1992
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Ingår i: Experimental Brain Research. - 0014-4819 .- 1432-1106. ; 89:1, s. 192-203
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Tidskriftsartikel (refereegranskat)abstract
- In the previous paper regarding the somatosensory control of the human precision grip, we concluded that the elicited automatic grip force adjustments are graded by the amplitude of the imposed loads when restraining an 'active' object subjected to unpredictable pulling forces (Johansson et al. 1992a). Using the same subjects and apparatus, the present study examines the capacity to respond to imposed load forces applied at various rates. Grip and load forces (forces normal and tangential to the grip surfaces) and the position of the object in the pulling direction (distal) were recorded. Trapezoidal load force profiles with plateau amplitudes of 2 N were delivered at the following rates of loading and unloading in an unpredictable sequence: 2 N/s, 4 N/s or 8 N/s. In addition, trials with higher load rate (32 N/s) at a low amplitude (0.7 N) were intermingled. The latencies between the start of the loading and the onset of the grip force response increased with decreasing load force rate. They were 80 +/- 9 ms, 108 +/- 13 ms, 138 +/- 27 ms and 174 +/- 39 ms for the 32, 8, 4 and 2 N/s rates, respectively. These data suggested that the grip response was elicited after a given minimum latency once a load amplitude threshold was exceeded. The amplitude of the initial rapid increase of grip force (i.e., the 'catch-up' response) was scaled by the rate of the load force, whereas its time course was similar for all load rates. This response was thus elicited as a unit, but its amplitude was graded by afferent information about the load rate arising very early during the loading. The scaling of the catch-up response was purposeful since it facilitated a rapid reconciliation of the ratio between the grip and load force to prevent slips. In that sense it apparently also compensated for the varying delays between the loading phase and the resultant grip force responses. However, modification of the catch-up response may occur during its course when the loading rate is altered prior to the grip force response or very early during the catch-up response itself. Hence, afferent information may be utilized continuously in updating the response although its motor expression may be confined to certain time contingencies. Moreover, this updating may take place after an extremely short latency (45-50 ms).
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| 9. |
- Jonsson, Maria, et al.
(författare)
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Heterogeneity of outer membrane proteins in Borrelia burgdorferi : comparison of osp operons of three isolates of different geographic origins.
- 1992
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Ingår i: Infection and Immunity. - : American Society for Microbiology. - 0019-9567 .- 1098-5522. ; 60:5, s. 1845-53
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Tidskriftsartikel (refereegranskat)abstract
- Biochemical and immunochemical studies of the outer membrane proteins of Borrelia burgdorferi have shown that the OspA and OspB proteins from strains of different geographic origins may differ considerably in their reactivities with monoclonal antibodies and in their apparent molecular weights. To further characterize this variation in Osp proteins between strains, the osp operons and deduced translation products from two strains, one from Sweden (ACAI) and one from eastern Russia (Ip90), were studied. Polyacrylamide gel electrophoresis and Western blot (immunoblot) analyses confirmed differences between ACAI, Ip90, and the North American strain B31 in their Osp proteins. The sequences of the ospA and ospB genes of ACAI and Ip90 were compared with that of the previously studied osp operon of B31 (S. Bergström, V. G. Bundoc, and A. G. Barbour, Mol. Microbiol. 3:479-486, 1989). The osp genes of ACAI and Ip90, like the corresponding genes of B31, were found on plasmids with apparent sizes of about 50 kb and are cotranscribed as a single unit. Pairwise comparisons of the nucleotide sequences revealed that the ospA genes of ACAI and Ip90 were 85 and 86% identical, respectively, to the ospA gene of strain B31 and 86% identical to each other. The ospB sequences of these two strains were 79% identical to the ospB gene of B31 and 81% identical to each other. There was significantly greater similarity between the ospA genes of the three different strains than there was between the ospA and ospB genes within each strain. These studies suggest that the duplication of osp genes in B. burgdorferi occurred before the geographical dispersion of strains represented by ACAI, Ip90, and B31.
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| 10. |
- Nilsson, Kjell G., 1953-
(författare)
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Kinematics and fixation of total knee arthroplasties : a clinical, radiographic, scintimetric, and roentgen stereophotogrammetric evaluation
- 1992
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aseptic loosening of the tibial component is an important cause of failure after total knee arthroplasty. Bone destruction often claimed to be caused by the cement makes the revision difficult. In order to treat younger patients, uncemented fixation has been introduced, but the etiology to loosening is multifactorial and only partly known. Early detection of implant migration facilitates research in this field but is difficult using conventional techniques. In this study modified versions of roentgen stereophotogrammetric analysis (RSA) were developed to obtain accurate and standardized evaluations facilitating comparison between prosthetic designs. The method was used to record the efficacy of cemented and uncemented fixation of different designs of the tibial component, to determine the accuracy of scintimetry in the detection of early aseptic loosening, and to analyse the in vivo kinematics of knee arthroplasties with different design and stability between the joint surfaces.Forty-three arthroplasties with comparatively high inherent stability of the joint surfaces were randomized to cemented or uncemented fixation of the tibial component. In all groups micromovements were rather large, but with no differences between the cemented and uncemented components. The preoperative diagnosis (arthrosis OA, n=25; rheumatoid arthritis RA, n=18) did not influence the magnitude of micromotion.20 arthroplasties with the same design as above but equipped with an intramedullary stem, were randomized to cemented or uncemented fixation in patients with RA. Cement improved the fixation. Uncemented stemmed components displayed micromovements seemingly larger than unstemmed ones.34 arthroplasties with an unconstrained design of the joint area and fixed to the tibia with four pegs were randomized to cemented or uncemented fixation in patients with OA. When used uncemented 4 screws were added. Compared with previously investigated designs small micromotions were recorded, and especially in the cemented cases. Uncemented components with thin polyethylene inserts displayed larger initial micromotions. The preoperative deformity influenced the direction of the micromotion.33 knees were followed prospectively with RSA and scintimetry to evaluate any correlation between these methods. Low activity under the tibial component at 2 years implied prosthetic stability, whereas high activity indicated instability or high bone remodelling caused by the preoperative malalignment.The in vivo kinematics in three different designs of knee arthroplasties were analyzed during active flexion and extension without weight-bearing. Each type of prosthesis displayed design-specific abnormalities when compared with a normal material. Pronounced posterior tibial translations were recorded during flexion regardless whether the posterior cruciate ligament had been sacrificed or not. Data from the kinematic and the fixation studies suggest that movements restricted by the design of the joint area are transmitted to the bony interface with design-specific micromotions as the result.Analysis of knee joint kinematics during extension and weight-bearing revealed small alterations compared with non-weight-bearing. Evaluation of the three-dimensional movements in terms of helical axis rotations and translations confirmed the constrained or unconstrained in vivo behaviour of the designs under study. This analysis also facilitated the interpretation of the kinematic behaviour of the prosthetic knees and may be of value in the evaluation of new designs.
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