| 11. |
- Aspenberg, P., et al.
(författare)
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Drug test chamber : a titanium implant for administration of biochemical agents to a standardized bone callus in situ
- 1988
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Ingår i: Journal of Biomedical Engineering. - : Elsevier BV. - 0141-5425. ; 10:1, s. 70-73
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Tidskriftsartikel (refereegranskat)abstract
- A titanium implant in which a conduit is gradually filled with ingrowing bone (the Bone Harvest Chamber) has been modified to allow continuous local treatment of the conduit tissue with biochemical agents. Implants were inserted bilaterally in rabbit tibiae. The tissue content of the bone ingrowth conduits was studied with histology, 99mTc-MDP scintimetry and measurements of total calcium content. Bone was formed in the conduit by endochondral formation starting at both ends and continuing until fusion in the middle. After 2 weeks the bone had not yet met in the middle where fibrous tissue was seen. In eight animals 3H-proline was applied via one of the chambers, with the contralateral chamber as a saline-treated control. The collagen of the harvested tissue from the 3H-proline treated side had a 3H-hydroxyproline content 1000 times greater than had the control side. The 'drug test chamber' makes possible the study of local effects of drugs on healing of mature bone in vivo.
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| 12. |
- Djerf, K, et al.
(författare)
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A simplified roentgen stereophotogrammetric method. Analysis of small movements between the prosthetic stem and the femur after total hip replacement.
- 1987
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Ingår i: Acta Radiologica. - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 28:5, s. 603-606
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Tidskriftsartikel (refereegranskat)abstract
- A simplified roentgen stereophotogrammetric method is described. It is based on the use of a 50 mm thick reference plate consisting of a carbon-fibre-reinforced polyester box. The patient is placed directly on this box, which makes the methods less cumbersome and more suitable for routine use. The method has been tested in a model experiment designed for detecting small movements between femur and prosthesis at an early stage after total hip replacement. The head and two hemispheres on the prosthesis and three small tantalum balls inserted in the femur serve as reference points. The model experiment now reported shows that the method has acceptable precision.
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| 13. |
- Elmqvist, Lars-Gunnar, 1944-
(författare)
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Chronic anterior cruciate ligament tear : knee function and knee extensor muscle size, morphology and function before and after surgical reconstruction
- 1988
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Knee function was evaluated by knee score, activity level, clinical findings and performance tests, muscle size by computerized tomography (CT), morphology by light (LM) and electron microscopy (EM), muscle function by electromyography (EMG) and isokinetic performance in 29 patients with chronic anterior cruciate ligament (ACL) tear. Preoperatively CT disclosed a significant mean atrophy of the quadriceps and nonsignificant changes of the other muscle areas of the injured leg. Morphology of m vastus lateralis of the injured leg was normal in more than half of the biopsies preoperatively, the rest showed signs of nonoptimal activation. Significant decreases in all isokinetic parameters were noticed together with significantly decreased EMG of the quadriceps muscle of the injured leg.Âfter surgical reconstruction the knees were immobilized in a cast for 6 weeks at either 30° or 70° of knee flexion. After cast removal CT showed significant decreases of all areas which also remained after training. The 30° group showed larger fibres (intracellular oedema) and more frequent morphological abnormalities than the 70° group. Fourteen weeks postoperatively the patients were allocated to either a combination of isometric and progressive resistance training or isokinetic training for 6 weeks. CT showed slightly larger areas at 20 weeks postoperatively than at 6 weeks. Morphological abnormalities were still prominent at 20 weeks postoperatively. Maximum isokinetic knee extensor mechanical output and endurance were markedly decreased at 14 weeks postoperatively but both improved progressively during the one year rehabilitation, mostly during the intensive 6 week training period but irrespective of training programme used. Fatiguability/endurance level improved over the preoperative level. Muscular work/integrated EMG was stable while EMG/t increased indicating neuromuscular relearning.The clinical result at 28 months foliowup was excellent or good in 93% of the patients and clinical stability improved in 66%. Independent upon primary knee immobilization angle or training programmes no differences could be demonstrated with respect to stability, range of motion, function or isokinetic mechanical output. Isokinetic performance was still significantly lower in the injured compared to the noninjured leg and not significantly different from the preoperative values. Morphology, only 6 cases, showed abnormalities similar to preoperative findings.In conclusion, the reason for the decreased maximum and total knee extensor performance in these patients with ACL tears is suggested to be nonoptimal activation of normal functioning muscle fibres depending on changes in knee joint receptor afferent inflow. No differences concerning the markedly improved postoperative clinical result could be seen between the different treatment modalities used. A nonoptimal muscular activation might explain the still decreased isokinetic performance present at followup.
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| 14. |
- Lexell, Jan, et al.
(författare)
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Distribution of different fibre types in human skeletal muscles. A statistical and computational model for the study of fibre type grouping and early diagnosis of skeletal muscle fibre denervation and reinnervation
- 1983
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Ingår i: Journal of the Neurological Sciences. - 1878-5883 .- 0022-510X. ; 61:3, s. 301-314
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Tidskriftsartikel (refereegranskat)abstract
- To define fibre type grouping in terms of random and non-random arrangements of the two fibre types, type 1 (ST) and type 2 (FT), we adopted the measure of counting the number of "enclosed fibres". The statistical properties of the number of enclosed fibres, and the number and size of groups of enclosed fibres were studied in computer-simulated muscle cross-sections, using a model based upon hexagonal-shaped fibres. The effects on the results of differences in the sizes of the muscle fibres were considered. The applicability of the model, and the derived results and methods of analysis were tested on 10 samples from a cross-section of a whole human muscle. The results show that the model can be applied to various shapes and sizes of muscle samples and various sizes of muscle fibres. The number of enclosed fibres within a muscle sample is the best of the three measures of non-randomness considered. A test is also described for assessing whether or not the observed number of enclosed fibres is random at a given significance level.
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| 15. |
- Lexell, Jan, et al.
(författare)
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Variability in muscle fibre areas in whole human quadriceps muscle: how to reduce sampling errors in biopsy techniques
- 1989
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Ingår i: Clinical Physiology. - 1365-2281 .- 0144-5979. ; 9:4, s. 333-343
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Tidskriftsartikel (refereegranskat)abstract
- A single biopsy is a poor estimator of the muscle fibre cross-sectional area (CSA) for a whole human muscle because of the large variability in the fibre area within a muscle. To determine how the sampling errors in biopsy techniques can be reduced, data on the CSA of type 1 and type 2 fibres obtained from cross-sections of whole vastus lateralis muscle of young men, have been analysed statistically. To obtain a good estimate of the mean fibre CSA in a biopsy, measuring all fibres in that biopsy gives the best result. To obtain a good estimate of the mean fibre CSA for a whole muscle, the number of biopsies has a much greater influence on the sampling error than the number of fibres measured in each biopsy, but the number of biopsies needed to obtain a given sampling error can vary by a factor of two. If the fibre CSA in three or more biopsies is measured, it is sufficient to measure only 25 fibres in each biopsy. If less than three biopsies are taken, there is no worthwhile reduction in sampling error when more than 100 fibres are measured. To determine the mean fibre CSA for a whole group of individuals, our preference is to maximize the number of individuals, and only take single biopsies. In conclusion, to determine the mean fibre CSA for this particular muscle with a certain precision, we suggest analysis of three biopsies, taken from different depths of the muscle, and measurement of 25 fibres in each biopsy.
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| 16. |
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| 17. |
- Romner, Bertil, et al.
(författare)
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Late magnetic resonance imaging related to neurobehavioral functioning after aneurysmal subarachnoid hemorrhage
- 1989
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Ingår i: Neurosurgery. - 0148-396X. ; 25:3, s. 390-396
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Tidskriftsartikel (refereegranskat)abstract
- Twenty patients who underwent early aneurysm surgery--that is, surgery within 72 hours after rupture--underwent further follow-up examination including magnetic resonance imaging (MRI) of the brain and a comprehensive neuropsychological assessment. Significant statistical correlation between tissue loss as seen on a late MRI scan and neurobehavioral deficits could not be established. Among 9 patients with no tissue loss seen on MRI, 3 exhibited substantial cognitive dysfunction and 6 had mild impairment. Three patients showed minor but corresponding tissue loss and deficits. In 3 patients with pronounced pathological indications on MRI, evidence of cognitive dysfunction was absent in 2, and 1 patient showed substantial impairment. The remaining 5 individuals displayed moderate pathological indications on MRI, with no obvious correspondence to cognitive functioning. In 7 patients, small white matter lesions, probably silent infarcts not seen on computed tomographic scan, were discovered on MRI. There was a clear relationship between arterial hypertension prior to aneurysm rupture and the extent of tissue loss seen on MRI. Absence of pathological findings on MRI scan did not exclude cognitive malfunctioning, and vice-versa.
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| 18. |
- Sjöberg, Trygve, et al.
(författare)
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The strong contractile effect of the thromboxane receptor agonist U-46619 in isolated human pulmonary arteries and its competitive antagonism by BM-13.505
- 1989
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Ingår i: Acta Physiologica Scandinavica. - 0001-6772. ; 136:2, s. 161-165
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Tidskriftsartikel (refereegranskat)abstract
- Ring segments (I mm in diameter) of the pulmonary artery obtained from 16 patients undergoing thoracic surgery were mounted in tissue baths. Cumulative concentration-response curves of some prostanoids and amines were obtained, and Emax and pEC50 values calculated. Noradrenaline, phenylephrine, clonidine and serotonin (5-HT) showed low intrinsic activities. Prostaglandin F2 alpha (PGF2 alpha) induced strong contractions with an Emax of 126% of the preceding K+ (124 mM)-induced contraction, but its potency was low (pEC50 = 5.70). The thromboxane receptor agonists U-46619 and U-44069 induced strong contractions (Emax = 139% and 133% respectively) and were significantly more potent than the other drugs used (pEC50 = 8.43 and 8.30 respectively). The thromboxane receptor antagonist BM-13.505 (10(-8) to 10(-6) M) caused rightward parallel shifts of the U-46619 concentration-response curves without reduction of Emax, indicating competitive antagonism.
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| 19. |
- Solem, Jan Otto, et al.
(författare)
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Hemoconcentration by ultrafiltration during open-heart surgery
- 1988
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Ingår i: Scandinavian Journal of Thoracic and Cardiovascular Surgery. - : Informa UK Limited. - 0036-5580. ; 22:3, s. 271-274
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafiltration was used during extracorporeal circulation (ECC) with heart-lung machine in 17 critically ill cardiac patients. In ultrafiltration (hemofiltration), water and small molecules (e.g. urea, creatinine and electrolytes), are separated from the blood by hydrostatic pressure generated on the blood side of a semipermeable membrane. The patients had severe water overload for three reasons, viz. congestive heart failure (10), renal failure (6) or iatrogenic extreme hemodilution (1). On average 2090 (800-5700) ml water was filtered off, increasing the hematocrit from 25 to 33%. Three indications for ultrafiltration during ECC and two modes of such treatment are exemplified in three case reports. No negative effect of the treatment was observed. Ultrafiltration during ECC thus may help to improve the postoperative course in patients with severe water overload due to congestive heart failure, renal failure or iatrogenic extreme hemodilution.
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| 20. |
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