Biomedical subjects

G Lundborg

Publications and source records attributed to G Lundborg.

At least 19 recordsLinked to original sources

PubMed2001

Test of swedish anti-skid devices on five different slippery surfaces.

The interest for effective preventive strategies for slips and falls is growing. Much remains to be done, however, to prevent slips and falls in the traffic environment. Some pedestrians are injured because of slippery pavements and roadways. Using an appropriate anti-skid device may reduce the risk of slips and falls on different surfaces outdoors during winter. The aim of this study was to evaluate new anti-skid devices on the Swedish market representing three different designs of anti-skid devices; heel device, fore-foot device and whole-foot device on different slippery surfaces, gravel, sand, salt, snow and ice. The evaluations were done according to subject's perceived walking safety and balance, videorecordings of walking postures and movements, time to take on and off each anti-skid device, advantages/disadvantages with each anti-skid device and a list of priority for own use according to three criteria; safety, balance and appearance. Practical tests were carried out on different slippery surfaces, gravel, sand, salt, snow and ice. The subject's were randomly selected from the registered population over 55 years in a city in northern Sweden. The results showed that eight or more of the ten subjects perceived all four anti-skid devices as fairly good or good regarding walking safety and balance when walking on gravel, sand, and salt. Anti-skid device 3, a whole-foot device was perceived as having none or bad walking safety and balance on snow by seven subjects and anti-skid device 4, a heel device, as having none or bad walking balance on ice by all ten subjects. Eight subjects walked with a normal muscle function in the hip and knee with all anti-skid devices on all surfaces. Small deviations in walking posture and movements were noted in one to two subjects when walking on different surfaces, but no systematic difference between the devices. Anti-skid device 1 'Rewa', a fixed heel device, was perceived as the most rapid one to take on. All four devices were perceived as easy to use and as giving good foothold. Anti-skid device 1 'Rewa' and 4 'Thulin-spike', both heel devices, had the highest priority according to walking safety. 'Rewa' also had the highest priority according to walking balance as well as own use. When combining the criterias 'Rewa' had the highest priority according to walking safety and balance, priority for own use, time to take on and easiness to use.

Accidental Falls↗

PubMed2000

Collateral sprouting from sensory and motor axons into an end to side attached nerve segment.

A nerve segment, sutured end-to-side (ETS) to an intact rat sciatic nerve, becomes invaded by regenerating axons. The origin of these fibres is controversial: it is debated whether or not they represent collateral sprouts from intact axons. Here we demonstrate by double retrograde tracing, using one tracer for the ETS attached segment and another for the sciatic nerve proper double-labelled sensory neurons in 67% of the rats receiving an ETS segments. Double-labelled motor neurons were observed in 11% of the rats. The results show that a nerve segment attached ETS to an intact nerve can induce collateral sprouting of both sensory and motor axons although the extent of such branching may vary with the experimental conditions.

Animals↗

PubMed2000

[Malpractice in connection with radius fractures must be reduced. Clear guidelines for treatment and follow-up are required].

PSR handles the vast majority of malpractice injuries in Sweden. PSR is a claims handling company which settles claims for malpractice on behalf of the insurance company owned by the Swedish county councils: the County Councils Mutual Insurance Company. A central issue in the law regulating patient injuries in Swedish health care is to define injuries that could have been avoided if a certain therapeutic/diagnostic procedure or a more appropriate method had been utilized. PSR arranged a multiprofessional conference regarding guidelines to decrease the number of malpractice injuries in the treatment of distal radius fractures. Among the most important issues defined were: To improve and standardize diagnostic imaging Patient information Early decision making in surgery and physical/occupational therapy A more well-defined indication for surgery, in which type of trauma, biological age and functional demands are considered in addition to radiographs Less stereotyped thinking in follow-up Controlled randomized trials.

Clinical Competence↗

PubMed2000

[Hand transplantation and implantation of nerve chips. New developments within hand surgery].

Injuries and diseases of the hand naturally have an enormous impact on hand function and on quality of life, both occupational and social. The majority of hand-injury patients are under 30 years of age. Hand surgery, an established specialty in Sweden since 1969, is of great importance in terms of clinical developments, education and research. In the coming decade, scientific and clinical advances are to be expected in several fields such as nerve injuries including brachial plexus lesion, microsurgery, flexor tendon injuries and tendon transfer. Bioimplant research and new advances at the biotechnological interface will yield new options in nerve reconstruction, microchip implants in the nervous system, and the restoration of muscle-tendon function following injury. Artificial limbs with advanced motor and sensory functions will be important future aids in the rehabilitation of amputees. Transplantation of human hands is another promising reconstructive procedure which may open iup new perspectives in the coming millennium.

Amputation, Surgical↗

PubMed2000

Pedestrians on slippery surfaces during winter--methods to describe the problems and practical tests of anti-skid devices.

Every year there are thousands of pedestrians in Sweden who are injured because of slippery pavements and roadways. Using an appropriate anti-skid device may reduce the risk of slips and falls on ice and snow. Methods to describe functional problems in walking on different slippery surfaces during winter have been developed as rating scales for evaluating walking safety and walking balance and an observation method to observe posture and movements during walking. Practical tests of all 25 anti-skid devices on the market in Sweden were carried out on different slippery surfaces; gravel, sand, salt, snow and ice. The anti-skid devices were described according to the subjects' perception of walking safety, walking balance and priority for own use. The postures and movements during walking were analysed by an expert physical therapist. The wholefoot device 'studs' was perceived as the best according to walking safety and walking balance and had the highest priority for own use.

Accidental Falls↗

PubMed2000

A 25-year perspective of peripheral nerve surgery: evolving neuroscientific concepts and clinical significance.

In spite of an enormous amount of new experimental laboratory data based on evolving neuroscientific concepts during the last 25 years peripheral nerve injuries still belong to the most challenging and difficult surgical reconstructive problems. Our understanding of biological mechanisms regulating posttraumatic nerve regeneration has increased substantially with respect to the role of neurotrophic and neurite-outgrowth promoting substances, but new molecular biological knowledge has so far gained very limited clinical applications. Techniques for clinical approximation of severed nerve ends have reached an optimal technical refinement and new concepts are needed to further increase the results from nerve repair. For bridging gaps in nerve continuity little has changed during the last 25 years. However, evolving principles for immunosuppression may open new perspectives regarding the use of nerve allografts, and various types of tissue engineering combined by bioartificial conduits may also be important. Posttraumatic functional reorganizations occurring in brain cortex are key phenomena explaining much of the inferior functional outcome following nerve repair, and increased knowledge regarding factors involved in brain plasticity may help to further improve the results. Implantation of microchips in the nervous system may provide a new interface between biology and technology and developing gene technology may introduce new possibilities in the manipulation of nerve degeneration and regeneration.

Anastomosis, Surgical↗

PubMed2000

A model instrument for the documentation of outcome after nerve repair.

We present a new model for documentation and quantification of the functional outcome after nerve repair at the wrist or distal forearm level and a protocol that includes a numerical scoring system. The model, presented here along with validation and reliability test results, supports our hypothesis that the summarized test results reflecting specific functional limitations correlates well with the patient's opinion of the impact of the nerve injury on activities of daily living. Seventy patients with nerve repair were examined using the protocol. Analysis included 3 factors: sensory domain (sensory innervation, tactile agnosis, and finger dexterity), motor domain (motor innervation and grip strength), and pain/discomfort domain (hyperaesthesia and cold intolerance). The analysis explained 73% of the variances of the variables and the variables had a logical distribution between the factors. Analysis of internal consistency demonstrated good homogeneity. A calculated total score correlated strongly with the patients' global estimation of the impact of the injury on activities of daily living and the summary of sensory and pain/discomfort domains correlated significantly with the Medical Research Council S0-S4 scale. The presented model represents a useful new tool for evaluation of the functional outcome after nerve injury and repair.

Adolescent↗

PubMed2000

Brain plasticity and hand surgery: an overview.

The hand is an extension of the brain, and the hand is projected and represented in large areas of the motor and sensory cortex. The brain is a complicated neural network which continuously remodels itself as a result of changes in sensory input. Such synaptic reorganizational changes may be activity-dependent, based on alterations in hand activity and tactile experience, or a result of deafferentiation such as nerve injury or amputation. Inferior recovery of functional sensibility following nerve repair, as well as phantom experiences in virtual, amputated limbs are phenomena reflecting profound cortical reorganizational changes. Surgical procedures on the hand are always accompanied by synaptic reorganizational changes in the brain cortex, and the outcome from many hand surgical procedures is to a large extent dependent on brain plasticity.

Brain↗

PubMed2000

Tomorrow's artificial hand.

Explore the source record for details and available documents.

Artificial Limbs↗

PubMed2000

Bioartificial nerve graft for bridging extended nerve defects in rat sciatic nerve based on resorbable guiding filaments.

A long defect (15 mm) in rat sciatic nerve was repaired with a bioartificial nerve graft composed of a silicone tube and seven synthetic filaments of five types (polyamide, catgut, polydioxanone, and two types of polyglactin, normal and quickly-absorbed) inserted longitudinally into the tube. In all cases in which filaments were used a regenerating bridge was obtained in the tube after three months in contrast to empty silicone tubes, in which no structure was observed. There was a 6%-46% recovery of isometric muscle contractility of the anterior tibial and gastrocnemius muscles with positive pinch reflex test in most cases. Myelinated axons were seen in the regenerating tissue between the filaments but not directly in contact with them, and there were varying numbers of macrophages close to the filaments. Silicone tubes with filaments, regardless of type of filament, induced nerve tissue to regenerate and resulted in functional recovery through a 15 mm nerve gap not achieved with empty tubes. Nerve promoting factors may be applied to the filaments and the model is a valuable tool for further development of artificial nerve grafts.

Animals↗

PubMed2000

Sutures alone are sufficient to support regeneration across a gap in the continuity of the sciatic nerve in rats.

We have proposed that it is sufficient to provide a simple substratum on which regenerating axons may traverse a gap in a peripheral nerve. To test this hypothesis we set up a new experimental model in which sutures were used to bridge a 10 mm long defect in a peripheral nerve. A defect was created bilaterally in 25 rat sciatic nerves. The cut ends of the nerve were joined by three laps of a continuous suture, on one side with 8/0 polyamide (non-absorbable) and on the other with 8/0 polyglactin (absorbable), leaving a 7 mm gap. At two weeks a matrix that contained capillaries, fibroblast-like cells, and mononuclear cells had formed between the nerve endings, and the sutures were surrounded by foreign-body-like tissue reactions. At four weeks axons had grown into the distal nerve segment on both sides in 65%-90% of the cases as indicated by a response to the pinch reflex test and immunocytochemistry for presence of neurofilament protein. Axons were organised in minifascicles and these tended to grow larger as the demarcation of the entire regenerated segment by a perineurial-like structure improved with time. At 12 weeks axonal counts of cross-sections of the distal tibial trunk showed many myelinated nerve fibres but no significant difference in axonal counts or degree of myelination between the polyamide and polyglactin sides. The results show that conventional sutures alone are sufficient to support regeneration across a short gap in a peripheral nerve, a method that may be of potential clinical value.

Animals↗

PubMed2000

Assessment of functional outcome after nerve repair in a longitudinal cohort.

To investigate the temporal changes in the results of clinical tests of the functional outcome after nerve repair, we followed up 19 patients periodically over a four year period after repair of the median or ulnar nerve at the forearm. Between the first and last follow-up four of the instruments used--Semmes-Weinstein monofilaments, manual muscle testing, Sollerman grip test, and Jamar dynamometer--indicated significant and moderate to large improvements. A moderate and significant improvement was also noted during the same period in patients' estimation of pain or discomfort. Results of the two-point discrimination test did not change significantly over time. Most changes occurred during the first postoperative year, and thereafter it was principally motor function that improved. We conclude that four of the six used tests showed useful temporal dynamics during the follow-up time. The lack of responsiveness in two-point discrimination test suggests that other or complementary test instruments should be used for assessment of tactile gnosis after nerve repair.

Adolescent↗

PubMed2000

Osseointegrated proximal interphalangeal joint prostheses with a replaceable flexible joint spacer--long-term results.

Osseointegrated proximal interphalangeal joint prostheses with a replaceable joint spacer were used in 25 joints in 19 patients (five men and 14 women) aged 45 (16-67) years. Indications for surgery were post-traumatic arthrosis (nine joints in eight patients), primary osteoarthrosis (10 joints in eight patients), and rheumatoid arthritis (six joints in three patients). A silicone joint spacer was attached to titanium fixtures by short titanium stems that extended from the spacer and fitted into a central canal in the screws. The arthroplasty was done in one stage, which included resection of the joint followed by grafting of marrow and cancellous bone from the iliac crest into adjacent medullary cavities before insertion of the titanium fixture. Follow up at 8.5 (5-11) years showed that 47 out of 50 fixtures (94%) had successfully osseointegrated while 17 of 25 joint spacers (68%) had fractured. However, because of the design of the prostheses fractured joint spacers could easily be replaced and a new spacer could be connected to already osseointegrated screws. The joint spacer was replaced in 11 fingers once or several times. Range of movement (ROM) in the whole series (four fusions excluded) was 41 (0-85) degrees with an extension defect of 15 (0-55) degrees. In eight joints with permanently intact joint spacers the ROM was 39 (0-60) degrees with extension defects of 16 (0-40) degrees. In six joints in which the spacer was replaced once the ROM was 43 (0-85) degrees with an extension defect of 16 (0-55) degrees. Our data confirm good long-term osseointegration of titanium fixtures and that a joint spacer, if needed, can be replaced by a new spacer that can be attached to already osseointegrated screws without jeopardizing the ROM.

Adolescent↗

PubMed1999

Vascular endothelial growth factor stimulates Schwann cell invasion and neovascularization of acellular nerve grafts.

The aim of this study was to investigate the effects of vascular endothelial growth factor (VEGF) on regeneration of the rat sciatic nerve in vivo. To that end we used 10-mm long cell-free nerve grafts to bridge a gap in the sciatic nerve. The grafts were pretreated with either VEGF (50, 100 or 250 ng/ml), nerve growth factor (NGF, 100 ng/ml) or laminin (100 ng/ml) before implantation. Outgrowth of axons, Schwann cells, blood vessels and macrophages were studied 10 days post-implantation by the use of immunocytochemistry and histochemistry. Grafts pretreated with VEGF stimulated the outgrowth of Schwann cells and blood vessels but not axons. In such grafts, the Schwann cells also exhibited a dramatic change in morphology and became filled with large lipid-containing vacuoles. These cells also showed an intense immunoreactivity for the VEGF receptor flk-1. Neither pretreatment with laminin nor NGF affected the outgrowth of Schwann cells. However, NGF treatment increased the number of axons in the graft but was not able to counteract injury-induced downregulation of substance P in the dorsal root ganglia. The results show that local application of VEGF promotes at least two events, invasion of Schwann cells and neovascularization, which are important during nerve regeneration. The findings suggest that the effects of the pretreatment by the growth factors is local and limited to the graft, whereas central events like neuropeptide synthesis is not affected.

Alkaline Phosphatase↗

PubMed1999

[Hand transplantation and implantation of nerve chips. New developments within hand surgery].

Amputation, Surgical↗

PubMed1999

Vascular endothelial growth factor has neurotrophic activity and stimulates axonal outgrowth, enhancing cell survival and Schwann cell proliferation in the peripheral nervous system.

Vascular endothelial growth factor (VEGF) is a mitogen for endothelial cells, and it promotes angiogenesis in vivo. Here we report that VEGF(165) has neurotrophic actions on cultured adult mouse superior cervical ganglia (SCG) and dorsal root ganglia (DRG), measured as axonal outgrowth. Maximal effect was observed at 10-50 ng/ml for SCG and 100 ng/ml for DRG. VEGF-induced axonal outgrowth was inhibited by the mitogen-activated protein kinase kinase inhibitor PD 98059 but not by the protein kinase inhibitor K252a. VEGF also increased survival of both neurons and satellite cells and the number of proliferating Schwann cells. Immunocytochemistry and immunoblotting revealed that VEGF was expressed in virtually all nerve cells in the SCG but only in a population of small-diameter (<35 micrometers) neurons representing approximately 30% of the neurons in DRG. Immunostaining showed that the VEGF receptor fetal liver kinase receptor (flk-1) was found on nerve cell bodies in DRG and to a lesser extent on neurons in SCG. Growth cones of regenerating axons from both types of ganglia exhibited flk-1 immunoreactivity, as did Schwann cells. We conclude that VEGF has both neurotrophic and mitogenic activity on cells in the peripheral nervous system.

Animals↗

PubMed1999

A role of migratory Schwann cells in a conditioning effect of peripheral nerve regeneration.

The common peroneal nerve in mice was conditioned by axotomy around the head of the fibula. At various intervals from 1 day to 2, 3, 5, 15, and 25 days, a test lesion was made by axotomy 15 mm proximal to the conditioning lesion site. The proximal stump of the transected nerve was sandwiched between two sheets of thin plastic film and remained in vivo for various intervals from 3 h to 6, 9, 12, 24, 48, 72 and 96 h. The regenerating axons were visualized on the film with silver nitrate impregnation. Schwann cells were visualized migrating onto the film using immunohistochemistry with anti-S-100. To determine the effects of migratory Schwann cells on axonal outgrowth, a film model was established on one limb. After the nerve stump was removed from the film, the treated film was transferred to a new lesion on the contralateral limb and 2 days later the film was harvested for histological examination. Conditioned by a prior axotomy more than 3 days earlier, regenerating axons sprouted within less than 1 h after the test lesion was established and grew naked at five times higher rate: The growth rate was similar to that observed during regeneration in the presence of migratory Schwann cells (ordinary type). After a short interval, the axons, which had been ensheathed by migratory Schwann cells (reactive type), continued growing at a significantly (P < 0.01) higher rate. The reactive type of cells had fewer numbers of branches and higher activity in promoting axonal outgrowth than the ordinary type. Thus, both ordinary and reactive types of cells played key roles in initiating and maintaining a conditioning effect, respectively.

Animals↗

PubMed1999

Spatiotemporal progress of nerve regeneration in a tendon autograft used for bridging a peripheral nerve defect.

We have previously shown that a tendon autograft from the rat tail can support regeneration across a gap in the continuity of the rat sciatic nerve. In this study, we characterized the spatiotemporal progress of regeneration in such a graft bridging a 10-mm defect in the sciatic nerve of the rat. Regeneration was assessed 7, 10, 14, or 18 days postoperatively, by immunocytochemistry for axons, Schwann cells, and macrophages and histochemistry for blood vessels. Axonal regrowth into the grafts showed an initial delay period of 6.8 days, whereafter axons grew at a rate of 1.0 mm/day. Schwann cells grew into the grafts from both the proximal and distal nerve segments, proximally just ahead of the axonal front. Macrophages were initially preferentially located at the periphery of the grafts, but gradually increased inside the grafts. Blood vessels entered the grafts from both the proximal and distal aspects of the severed nerve. The onset of vascularization appeared to coincide with axonal regeneration into the grafts.

Alkaline Phosphatase↗