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Biomedical subjects

J Johansen

Publications and source records attributed to J Johansen.

144 records · Page 8Linked to original sources
PubMed1977

Tibial shaft fractures. A comparison of conservative treatment and internal fixation with conventional plates or AO compression plates.

Out of a series of 207 consecutive fractures of the tibial shaft, 102 were treated conservatively, 64 fractures were treated by AO compression plate osteosynthesis and 41 by internal fixation using Eggers or Lane plates. The choice of method was independent of the extent of soft tissue damage. A follow-up examination of 199 fractures, with a mean observation time of 3.4 years, revealed residual malalignment in 21 per cent of conservatively treated cases and in 8 per cent after conventional plate fixation, while the AO method resulted in anatomical restoration of the axis of the tibia in all cases. However, removal of the compression plates was followed by re-fractures, early and late, in 11 per cent. Implant failure occurred in 5 per cent of both types of plate fixation, and 3 per cent of the conservatively treated cases redislocated. Infection developed in 5 per cent of closed fractures and in 11 per cent of open fractures treated by operative means. Of the conservatively treated cases, only 3 per cent of the open fractures developed infection. The risk of infection following acute internal fixation is thus four times greater than with conservative treatment. AO compression plate fixation shortened the time of fracture healing considerably. The rate of non-union after conservative treatment was 6 per cent in closed and 21 per cent in open fractures. Similarly in conventional plate fixation there was non-union in 8 and 24 per cent, respectively. Non-union was not encountered after AO compression plate osteosynthesis. It is concluded that AO plate osteosynthesis is justified in the treatment of open tibial shaft fractures and also useful in closed fractures when conservative treatment does not lead to stable reduction with a good alignment.

Adolescent↗
PubMedDate not supplied

The DaNeX study of embryonic mesencephalic, dopaminergic tissue grafted to a minipig model of Parkinson's disease: preliminary findings of effect of MPTP poisoning on striatal dopaminergic markers.

A multicenter study is under way to investigate the efficacy of allografting of embryonic mesencephalic neurons in a pig model of Parkinson's disease. We have first established that a stable parkinsonian syndrome can be established by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication of adult male Göttingen minipigs. We are now using positron emission tomography (PET) methods for testing the physiological responses to MPTP intoxication and the time course of the response to several treatment strategies. We now report preliminary results obtained in 11 pigs employed in the initial phase of the study; the completed study shall ultimately include 30 pigs. Animals were randomly assigned to one of five groups: 1) Control, 2) MPTP intoxication, 3) MPTP intoxication followed by allograft, 4) MPTP intoxication followed by allograft with immunosuppression, and 5) MPTP intoxication followed by allograft with immunosuppression and co-grafting of immortalized HiB5 cells, which had been manipulated to secrete glia cell line-derived neurotrophic factor (GDNF) (approximately 2 ng GDNF/h/10(5) cells). MPTP was administered (1 mg/kg/day, SC) for 7-10 days until the pigs had developed mild parkinsonian symptoms of muscle rigidity, hypokinesia, and impaired coordination, especially of the hind limbs. Approximately 2 weeks after the last MPTP dose, animals received a T1-weighted magnetic resonance imaging (MRI) scan, and a series of dynamic PET recordings. After the first series of PET scans, four grafts of porcine embryonic mesencephalic tissue (E28 days) were placed in each striatum of some MPTP-intoxicated pigs, using MRI-based stereotactic techniques. Immunosuppression of some animals with cyclosporin and prednisolone began just prior to surgery. Two more series of PET scans were performed at 4-month intervals after surgery. After the last scans, pigs were killed and the brains were perfused for unbiased stereological examination of cytological and histochemical markers in striatum and substantial nigra. The behavioral impairment of the animals (the "Parkinson's score") had been evaluated throughout the 8-month period. Kinetic analysis of the first set of PET scans has indicated that the rate constant for the decarboxylation of FDOPA in catecholamine fibers was reduced by 33% in striatum of the mildly parkinsonian pigs. The rate of association of [11C]NS-2214 to catecholamine uptake sites was reduced by 62% in the same groups of pigs. No significant difference was found in the binding potential of [11C]raclopride to the dopamine D2-like receptors in striatum of the MPTP-intoxicated versus control pigs. These preliminary results are suggestive that the activity of DOPA decarboxylase may be upregulated in the partially denervated pig striatum.

Animals↗
PubMedDate not supplied

Sjögren's syndrome.

Sjögren's syndrome is a multisystemic connective tissue disease. The syndrome is associated with other major connective tissue disorders, such as rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis and others, Reticulo-endothelial malignances have repeatedly been reported in patients with Sjögren's syndrome. A clinical study of 20 patients with Sjögren's syndrome was performed in the Department of otolaryngology, Rikshospitalet, Oslo, Norway. A considerable complexity of symptoms was seen. One patient with malignant lymphoma and one with a thyroid carcinoma were encountered.

Adolescent↗
PubMedDate not supplied

Animal model for studying the chronic effects of herniated disks and spinal surgery.

A successful model to study both herniated intervertebral disks and spinal operations such as laminectomy has not been described. Two procedures were developed in nonhuman primates: One produces an elevated nerve root simulating a herniated disk; the second is a laminectomy that simulates the operation in humans. Twenty-five surgical procedures were performed with no complications. A myelographic abnormality typical of a disk herniation results from the simulated disk herniation. The chronic effects of herniated disk and spinal surgery can be studied with this model.

Animals↗