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Biomedical subjects

G Lundborg

Publications and source records attributed to G Lundborg.

At least 127 records · Page 7Linked to original sources
PubMed1992

Vibrotactile function of the hand in compression and vibration-induced neuropathy. Sensibility index--a new measure.

The perception thresholds for vibration stimuli of the hand at seven frequencies (8-500 Hz) were evaluated in 300 patients referred to the Department of Hand Surgery in Malmö during the years 1985-1990 for various types of neuropathy (carpal tunnel syndrome, vibration-induced neuropathy, cervical rhizopathy, brachialgia, ulnar neuropathy, radial tunnel syndrome, and polyneuropathy). A sensibility index was calculated by dividing the integrated area under the obtained vibrogram curve of each object tested (areaT) by that of the corresponding area under a superimposed and age matched reference curve (areaR). Sensibility index of less than 0.8 was regarded as the cut off value. The index and little fingers bilaterally were tested to reflect median and ulnar nerve function. There were considerable variations in patterns of pathology among the various groups of patients. In patients with unilateral carpal tunnel syndrome only 10 patients (23%) had abnormalities limited to one recording, while 21 patients (47%) showed abnormalities in all four recordings. This indicates that an isolated carpal tunnel syndrome may reflect more generalised disease of the peripheral nervous system.

Carpal Tunnel Syndrome↗
PubMed1992

Reconstruction of ligaments with expanded polytetrafluoroethylene. An experimental study in rabbits.

The medial collateral ligaments in the knee joints of 15 rabbits were replaced with expanded polytetrafluoroethylene (E-PTFE). The joints were not immobilised postoperatively, and their structure and function were evaluated after 12 months. Range of motion was equal in all groups. Stability of the knee joints and breaking strength of the ligaments were similar in the group in which the ligament had been reconstructed and in the sham operated control group (n = 8). The group in which the ligament had been severed and left to heal by formation of scar tissue (n = 7) had significantly reduced joint stability and the breaking strength of the medial collateral ligament was significantly less. The E-PTFE ligaments were well incorporated into the surrounding tissues. There were no adverse tissue reactions and the articular cartilage looked normal both macroscopically and microscopically. These results indicate that E-PTFE might be a useful substitute for damaged ligaments, at least in smaller joints like metacarpophalangeal and interphalangeal joints.

Animals↗
PubMed1992

The pathophysiology of nerve compression.

The basic pathophysiology of an acute and chronic nerve compression lesion is complex. Compression of a peripheral nerve induces marked changes in intraneural microcirculation and nerve fiber structure, impairment of axonal transport, and alterations in vascular permeability, with edema formation and deterioration of nerve function. The peripheral nerves of subjects with underlying neuropathies are more susceptible to compression injury.

Humans↗
PubMed1991

Does insulin-like growth factor I (IGF-1) trigger the cell body reaction in the rat sciatic nerve?

Regeneration was measured after the infliction of a crush lesion on rat sciatic nerves which 4 days earlier had been subjected to a distal conditioning transection. Such nerves exhibited an increased outgrowth of nerve fibers as compared to nerves subjected to a single crush lesion. This increased outgrowth could be prevented, if the nerve was locally perfused around the site of the transection during the 4 days conditioning interval, with cycloheximide, actinomycin D and vinblastine, inhibitors of protein-, RNA-synthesis and retrograde axonal transport, respectively. The inhibitory effect of cycloheximide could be overcome by simultaneous perfusion with insulin-like growth factor I (IGF-1). The results suggest that proteins including IGF-1 which are synthesised locally around a nerve lesion and then transported retrogradely could trigger regenerative events in the neuronal cell body.

Animals↗
PubMed1991

Recombinant human insulin-like growth factor-I stimulates in vitro matrix synthesis and cell proliferation in rabbit flexor tendon.

Flexor tendons have an intrinsic ability for repair, with a capacity to metabolize matrix components and to proliferate. To identify factors with the potential of affecting those abilities, the effects of recombinant human insulin-like growth factor (rhIGF-I), insulin and fetal calf serum (FCS) on the synthesis of proteoglycan, collagen, and non-collagen protein and cell proliferation were investigated in short-term explant cultures of the deep flexor tendon of the rabbit. Matrix synthesis and cell proliferation were stimulated dose dependently by rhIGF-I at doses between 10 and 250 and at 10-100 ng/ml, respectively, by insulin at 250-5,000 ng/ml, and by FCS at 2-15%. Estimated maximal stimulation (Emax) of up to three times the control value was observed with rhIGF-I at 250 ng/ml. Maximal stimulation was observed at 5,000 ng/ml with insulin, and FCS at 15%. rhIGF-I was more potent than insulin in stimulating protein synthesis and cell proliferation. The Emax of stimulation of proteoglycan and collagen synthesis by rhIGF-I were two times that of FCS, and the Emax of cell proliferation by FCS was twice that of rhIGF-I. Growth factors thus have the ability to stimulate matrix synthesis and cell proliferation in rabbit flexor tendon. This provides a rationale for further studies on the role of growth factors in flexor tendon healing in humans.

Animals↗
PubMed1991

Long-term explant culture of rabbit flexor tendon: effects of recombinant human insulin-like growth factor-I and serum on matrix metabolism.

The effects of human recombinant insulin-like growth factor-I (rhIGF-I, 50 ng/ml) on matrix metabolism in the deep flexor tendon from the tendon sheath region of the rabbit were studied in explants cultured for 3 weeks. Tendon segments cultured in medium supplemented with fetal calf serum (FCS) exhibited proliferation of the superficial cell layers. Synthesis of proteoglycan and non-collagen protein (NCP) increased threefold during the first week and remained elevated during the next 2 weeks of culture in medium supplemented with rhIGF-I or FCS, but not in medium without supplements (bovine serum albumin, BSA). The estimated halflife (t1/2) for elimination of newly labeled proteoglycans from the tendon explants ranged from 5.1 to 8.5 days and from 4.9 to 6.8 days for NCP in supplemented medium. Presence of rhIGF-I or FCS did not affect degradation of matrix as compared with BSA. The total hexosamine content per tendon segment was stable during the culture period, but the non-collagen protein content decreased by 25%. Collagen synthesis decreased to 10% of the initial level after 3 weeks in supplemented medium, but to 3% in unsupplemented medium. There was no measurable turnover of collagen in explants cultured in either medium, and the collagen content remained unchanged. Our results suggest that rhIGF-I, as well as FCS, stimulates matrix synthesis but does not influence matrix turnover in rabbit flexor tendon explants in long-term culture as compared with medium without supplements. We conclude that rhIGF-I may be used as a defined growth-promoting factor in serum-free media and may be of importance in tendon healing.

Animals↗
PubMed1991

Neurotropism, frozen muscle grafts and other conduits.

Axonal regeneration following nerve transection requires a number of cellular and biochemical phenomena in the axons as well as the nerve cell bodies. The nerve cells must survive the trauma. Since axonal severance means amputation of a large axoplasmic volume from the remaining parts of the nerve cell, the cell body must prepare for increased synthesis of axoplasm to replace the missing parts. A sprouting process must be initiated at the level of transection. Regenerating axonal processes are to regenerate towards peripheral targets, a process regulated by an interaction between genetic mechanisms in the nerve cell body and biochemical information at the molecular level along the pathway.

Animals↗
PubMed1991

Effect of drying on regenerating rat sciatic nerve.

To study the effects of drying on regeneration, crush lesions were made on the sciatic nerve of 38 rats and the injured area was then air-dried for various periods of time (0-60 min). The regeneration distance of sensory nerve fibres was measured by the pinch reflex test three or six days later. Regeneration was significantly impaired by drying the nerve for 30 or 60 min, but shorter periods (10 min) also seemed to affect axonal outgrowth. Regeneration distances were increased in nerves that were subjected to drying and then allowed to recover for a week (conditioning interval) before the nerve was crushed. The results show that drying of a peripheral nerve is detrimental to nerve regeneration, and we suggest that nerves should not be exposed to air for more than a few minutes during operation without irrigation.

Animals↗
PubMed1991

Reconstruction of flexor tendon pulley with expanded polytetrafluoroethylene (E-PTFE). An experimental study in rabbits.

Gore-Tex (expanded Polytetrafluoroethylene, E-PTFE) was used to replace the distal pulleys on the proximal phalanges of 20 rabbits. Morphology and function of the reconstructed pulleys were evaluated at 12-20 weeks. The breaking strength of the E-PTFE pulley equalled that of a normal pulley. Range of motion, tendon excursion, and force of flexion were no different from those of normal pulleys. No adhesions between flexor tendons and synovial tendon sheaths or the E-PTFE pulleys could be detected. No adverse tissue reactions were seen. Fibroblast-like cells from the surrounding tissues had grown into the membrane. In other experiments, where the pulleys had been either removed or detached, local fibrosis and adhesions were seen, and the deep flexor tendons had ruptured. The results of the present study indicate that E-PTFE can be used as a biosynthetic replacement for damaged pulleys.

Animals↗
PubMed1991

Abductor pollicis longus tendon arthroplasty for treatment of arthrosis in the first carpometacarpal joint.

A retrospective study of 21 hands in 19 patients was carried out to show the results after excision of the os trapezium for the treatment of arthrosis of the first carpometacarpal joint. A technically easy procedure was used that was based on a tendon plasty using the abductor pollicis longus (APL) tendon. Special attention was paid to the effects of compressive load on the stability of the thumb. The mean follow-up time was 25 months (range 11-38) and all patients achieved good mobility. Pain was reduced in all cases but one. In operated hands grip strength was 84% of estimated normal strength and pinch strength 83%. On radiographs of the hands the mean distance between the base of the metacarpal bone and the scaphoid bone was 4.6 mm, this was reduced by 1.9 mm during compression. When radiographs were taken during a compressive load, two dislocations of the thumb base were found that had otherwise been missed.

Aged↗
PubMed1991

Ulnar nerve repair by the silicone chamber technique. Case report.

The ulnar nerve of a 21-year old man was repaired at the wrist by a silicone chamber technique 10 days after a traumatic transection. A 3 mm gap was left between the nerve ends inside the chamber. At follow-up three years later, motor and sensory recovery was excellent. At exploration at that time a macroscopically normal nerve was found in the tube.

Adult↗
PubMed1991

Functional splinting versus plaster cast for ruptures of the ulnar collateral ligament of the thumb. A prospective randomized study of 63 cases.

In a prospective randomized study that included 63 consecutive thumbs with injuries of the ulnar collateral ligament of the metacarpophalangeal (MCP) joint of the thumb, plaster cast immobilization was compared with functional treatment with a splint. The splint allowed flexion and extension of the MCP joint, but prevented ulnar and radial deviation of the thumb. The study included both operated on and nonoperated on cases where surgery was performed only when the torn ligament was regarded as displaced. Of 40 thumbs treated nonsurgically, 21 were treated with a cast and 19 with a splint. Of 23 thumbs treated surgically, 10 were immobilized postoperatively in a plaster cast and 13 were treated with the splint. At the follow-up examination after 15 (11-41) months, there was no difference between the treatment groups as regards stability, range of motion, strength of the injured thumb, and length of sick leave. However, the patients considered the splint more comfortable than plaster cast immobilization. We conclude that immobilization of the thumb after a ligamentous injury with a movable splint is strongly preferred by the patients and that the functional results of this technique are equal to plaster cast immobilization after both surgical and nonsurgical treatment.

Adolescent↗
PubMed1991

Dehydration inhibits matrix synthesis and cell proliferation. An in vitro study of rabbit flexor tendons.

Segments of the deep flexor tendon of the rabbit were exposed to air; the effects of dehydration on in vitro synthesis of proteoglycan, collagen, noncollagenous protein, and cell proliferation were compared with tendon segments that were kept moist with physiologic saline. After 20 min of exposure to air, the tendons lost half and after 40 min all of their ability to synthesize matrix components and to proliferate, whereas irrigated tendons remained viable during the entire experiment.

Animals↗
PubMed1990

The neurone and its response to peripheral nerve compression.

In all types of peripheral nerve injury, it is important to realize that the lesion affects one extended cell, the neurone, which extends from the central nervous system down to the target tissue in the extremity. Compression of a peripheral nerve can disturb the intraneural transport (axonal transport) of a large variety of substances. This may be followed by morphological and biochemical changes in the nerve cell body. These central changes may effect the axon as a whole and confer on the nerve an increased susceptibility to trauma. Studies concerning the reaction of neurones to compression, relevant when discussing the double crush syndrome, are reviewed.

Animals↗
PubMed1990

Diagnosis of displaced ulnar collateral ligament of the metacarpophalangeal joint of the thumb.

In a prospective study of 24 consecutive patients with posttraumatic instability of the metacarpophalangeal joint of the thumb, clinical examination including instability tests and palpation of displaced ulnar collateral ligaments was used to separate the patients into two groups--nondisplaced and displaced ruptures. Palpable displaced ruptures were treated surgically, whereas nonpalpable ruptures were interpreted as nondisplaced and were treated with plaster, irrespective of the instability. At follow-up 1 year later both groups showed similar results with respect to stability, strength, and function. Our results indicate that a clinical examination with palpation of the torn ligament ends identifies displaced ruptures of the ulnar collateral ligament, i.e., those cases needing surgery. Nondisplaced ruptures might be treated nonoperatively.

Adolescent↗