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Biomedical subjects

P Wehling

Publications and source records attributed to P Wehling.

At least 37 records · Page 2Linked to original sources
PubMed1994

Identification of S-locus linked PCR fragments in rye (Secale cereale L.) by denaturing gradient gel electrophoresis.

Rye inbred lines segregating at the S-locus and homozygous at the Z-locus were investigated by PCR with primers derived from Brassica SLG-sequences. After denaturing gradient gel electrophoresis (DGGE), a 280 bp PCR-fragment displays a polymorphism perfectly correlated to the underlying S-genotypes. This is the first report on S-related DNA polymorphism in a bifactorial self-incompatibility system of the Poaceae.

Alleles↗
PubMed1992

The influence of bacterial collagenase on regeneration of severed rat sciatic nerves.

Regeneration of peripheral nerve fibers is impeded by the formation of scar tissue at the site of injury. The possible beneficial effect of collagenase on nerve regeneration was studied using clinical, neurophysiological (evoked potentials) and histological (nerve fiber counts) methods. The sciatic nerves of rats were transected and the severed ends abutted and sewn together. In one series, the area about the lesion was covered with fibrin adhesive and infused with either isotonic saline (controls) or collagenase (treatment group). In the other series, the severed ends of the nerve were inserted into a silicone tube and separated by a collagen plug, which was infused with either saline or collagenase. Compared to the controls, the treated animals showed a significant improvement of clinical and neurophysiological parameters. After 3 months of observation, the collagen content of the transection site was reduced, and in the silicone series, the total number of myelinated axons 5 mm distal to the site of transection was increased, while the fiber diameter distribution was unchanged.

Animals↗
PubMed1990

Intrathecal injection of a specific enzyme in rats as a model for chemically induced spinal cord injury.

A spinal cord injury model is described using chymopapain as a neurotoxic agent in rats. The trauma was evaluated by neurophysiological and morphological methods. Electrically evoked compound action potentials were used to quantify the neurophysiological effects caused by the injection of chymopapain into the lumbar dural theca in rats. A branch of the sciatic nerve was stimulated with voltage impulses of constant amplitude (40 V) and duration (0.1 ms) at the right external malleolus. The responses were recorded at the dorsal root entry zone L1. We used different doses of the enzyme (1000 i.u./ml; 2500 i.u./ml; 5000 i.u./ml). A total amount of 0.1 ml was injected into the rats' lumbar spinal canal intrathecally (n = 18). The control rate (n = 8) were subjected to exactly the same stimulus and recording procedures but the test solution was a corresponding volume of isotonic saline. Two hours after injection the animals were examined clinically and then sacrificed for histology. The prolongation of the latency of the electrically evoked potentials caused by the enzyme was very clear at the doses of 2500 i.u. and 5000 i.u. being about 10-15% relative to the mean latency before administration of the drug. The histological evaluation showed hemorrhage, vascular damage and indirect signs of myelin edema of the lumbar nerve tissue. Our study indicates that chymopapain injections into the lumbar spinal canal can be used as a reproducible model for spinal cord injury research.

Animals↗
PubMed1989

[Chip fracture of the lateral tibial condyle--a roentgenologic sign of anterior cruciate ligament injury].

A case report serves as basis for describing the importance of the so-called chip fracture as the first roentgenological pointer to a rupture of the anterior cruciate ligament in a handball player. The paper discusses the biomechanical changes resulting from an ACL rupture and underlines the importance of early arthroscopic diagnosis or of arthroscopic surgery for regaining knee stability and for preventing secondary subsequent damage.

Adult↗
PubMed1989

[Clinical deterioration following chemonucleolysis. Sequestration or neurotoxic complication?].

The clinical deterioration in a patient after chemonucleolysis with chymopapain is described in a case report. Experiments were carried out, to receive a proper understanding of possible diagnostic and therapeutic approaches. The paper discusses the pathophysiology of these complications from the view-points of morphology and function. In the important early differential diagnosis between sequestration and neurotoxic complication, magnetic resonance tomography and possibly also spinally evoked nerve potentials play an important role. If a sequester has formed, immediate surgery is imperative, whereas in neurotoxic complication high dosage level cortisone treatment must be performed.

Adult↗
PubMed1989

Electrophysiological investigations in adoptively transferred experimental autoimmune encephalomyelitis in the Lewis rat.

Lewis rats with experimental autoimmune encephalomyelitis transferred adoptively with myelin basic protein-specific T line cells (AT-EAE) were studied clinically, electrophysiologically, and histologically. Injection with 5 x 10(6) line cells induced EAE with a rapidly developing tetraplegia after a latent period of 4 days. Electrophysiological testing revealed a profound slowing of afferent conduction within the dorsal column of the spinal cord, and conduction abnormalities in the spinal roots. Injection with a lower cell dose of 1 x 10(6) T line cells caused only moderate clinical signs paralleled by milder conduction slowing and conduction failure. Light microscopy showed marked inflammation with infiltration of mononuclear cells and some demyelination throughout the spinal cord and roots. Inflammation and demyelination were dose dependent and the caudal parts of the spinal cord were more affected than the cranial parts. The peripheral nerves were free of electrophysiological and morphological alterations. Systemic treatment with 4-aminopyridine accelerated and partially restored conduction in the dorsal columns and roots, while increasing the body temperature had a detrimental effect, suggesting demyelination as a prominent pathophysiological mechanism. These findings show that in AT-EAE in Lewis rats the dysfunction of the central nervous system and of spinal roots is cell dose dependent, that the peripheral nervous system distal to the spinal roots is spared, and suggest that paranodal demyelination is an important pathogenic mechanism.

4-Aminopyridine↗
PubMed1989

The influence on spinal cord evoked potentials of chymopapain applied to the rat lumbar spine canal.

Electrically evoked compound action potentials were used to quantify the neurophysiologic abnormalities caused by application of chymopapain into the lumbar spinal canal in rats. A branch of the sciatic nerve was stimulated with voltage impulses of constant amplitude (40 V) and duration (0.1 msec) at the right external malleolus. The responses were recorded at the dorsal root entry zone L1. The authors used different doses of chymopapain (low dose = 100 IU, middle dose = 250 IU, and high dose = 500 IU). The control rats were subjected to exactly the same stimulus and recording procedures, but the test solution was a corresponding volume of isotonic saline. The prolongation of the latency of the electrically evoked potential due to chymopapain is very clear at the doses of 250 IU and 500 IU, being about 10 to 15% relative to the mean latency before application of the drug. This study indicates that locally applied chymopapain has a dose-dependent effect on nerve conduction properties.

Animals↗
PubMed1988

[Early functional and structural changes in the nerve tissue following contact with chymopapain].

Using magnetic resonance imaging, conventional histology, and spinal evoked potentials, the authors studied the short-term effects of chymopapain on nerve tissue in the lumbar vertebral canal region in rats. Chymopapain in different concentrations was injected into the subarachnoid space in 31 rats. As early as 20 minutes later latency changes in the evoked potentials were observed; the histologic examinations after two hours showed bleeding, swelling of the myelin, and vascular changes. Magnetic resonance imaging of the lumbar spine, performed after six hours, showed a markedly stronger signal, indicative of an intraspinal edema, as compared to the control group. The authors' studies are clear proof that changes in nerve tissue following contact with chymopapain occur considerably faster than hitherto assumed in the literature.

Animals↗
PubMed1988

[Long-term studies of the reproducibility of evoked spinal potentials from chronically implanted recording electrodes in the rat].

Over a period of 4 weeks we examined the reliability of spinal cord nerve potentials in the thoracic-lumbar region after stimulation of the hindpaw in 10 rats. Recording electrodes were chronically implanted over a period of 4 weeks into the lower thoracic and upper lumbar lamina by using an operation microscope. The action potentials were recorded at the dorsal root entry zone after stimulating the hindpaw. By comparing the data of the recording sessions we found a high reliability of the spinal cord evoked response over a long period. The experimental model is appropriate for the assessment of neurophysiological changes in the long term. Additionally we examined some basic characteristics of the evoked spinal response in this area.

Animals↗
PubMedDate not supplied

[Bone density and bone metabolism regulated by vitamin D receptor allele polymorphism in a German study sample].

BACKGROUND: It has been reported that the spinal bone density is associated with vitamin-D-receptor (VDR) gene polymorphisms. The results of recent studies have been contradictory concerning the predictive power for low bone mineral density (BMD). Regional population-specific influences have been found to affect the vitamin-D-endocrinologic-system, diminishing the influence of VDR polymorphism on BMD and on bone turnover. We have examined the association of bone density, fracture predictivity and biochemical markers of bone turnover with VDR polymorphism in a German population. METHODS: Blood and urine were collected from a heterogeneous subset of 164 caucasian subjects with ethnic German background. Polymerase chain reaction and subsequent digestion with Bsm I were used to examine variations of VDR genotypes. The morning following initial specimen collections, both urinary excretion rate of pyridinoline crosslinks (Pyr) and serum levels of bone alkaline phosphatase (BAP) were determined. For determination of the bone mineral density, the well-established method of dual X-ray absorptiometry was used. FINDINGS: The VDR BB-genotype was associated with low bone mineral density for age-matched subjects (90.1 +/- 15.5%) versus the bb-genotype (100.8 +/- 10.8%) at the lumbar spine and at the Ward's triangle (91.8 +/- 17.9% versus 101.9 +/- 12.1%). 34.2% of BB-genotype subjects, 14.2% of bB-genotype subjects and 12.6% of bb-genotype subjects had Z-score related bone mineral density < 85%. The fracture rate at typical osteoporotic fracture sites was 23.6% for the BB-, 10.8% for the bB- and 0.0% for the bb-genotype. The urinary excretion rate of free pyridinoline crosslinks was higher for the BB-genotype than for the bB- or the bb-, however the difference was not significant. No genotype specific variations were seen for bone alkaline phosphatase. INTERPRETATION: The authors conclude from this study that bone mineral density at the axial skeleton is associated with the vitamin-D-receptor allele polymorphism and that there is an influence on bone turnover and fracture rate in a German subset. CLINICAL RELEVANCE: The analysis of the VDR-genotype can be considered as a new piece in the puzzle of the diagnostic of osteoporosis for we get prognostic hints concerning the rate of fracture.

Adult↗
PubMedDate not supplied

[Role of transcranial magnetic stimulation in the diagnosis of cervical root compression and cervical myelopathy].

We were interested in the question, if transcranial magnetic stimulation of nerve structure can be used in the objective description of motor impairment in humans with cervical nerve root compression and myelopathies. We could demonstrate, that paresis is combined with an increase of the latency of the evoked muscle potentials. Applications of the method in Orthopaedics and Neurosurgery involve description of motor deficits in cervical compression radiculopathy and myelopathy. Although the value of the method for orthopaedic and neurosurgical purposes is not yet clear, our experiences indicate interesting diagnostic possibilities in cervical spine diagnostics.

Cervical Vertebrae↗
PubMedDate not supplied

[In vitro transfer of genes in spinal tissue].

INTRODUCTION: It is well known that cytokines are involved in the induction of intervertebral disc and articular cartilage destruction. Therapeutic proteins are of great potential as locally produced drugs after transfer of their cognate genes to the sites of interest. METHODS: Chondrocytic cells from bovine os coccygis and discal chondrocytes from 6 wistar rats were isolated and cultured in vitro. The bacterial beta-galactosidase (LacZ) gene and the cDNA of the human interleukin-1 receptor antagonist (IL-1ra) were introduced into the cells by retrovirus mediated gene transfer. LacZ activity was determined by Xgal staining, IL-1ra protein was determined by ELISA. RESULTS: Our study confirms that isolation and cultivation of bovine chondrocytic end plate cells and of rat discal cells in possible. Transfer of both LacZ and of the IL-1ra cDNA to cultured cells was successfull. DISCUSSION: The introduction of exogenous therapeutical genes into cells from the intervertebral disc and the end plate opens the possibility for a local gene therapy of IVD degeneration. This therapy has the potential to be specific, effective and appropriate to the chronicity of the disease.

Animals↗
PubMedDate not supplied

[Perspectives in gene therapy in rheumatic and degenerative diseases of the spine and joints].

Rheumatoid degenerative conditions of the spine and other joints are most common in elderly patients. Data by the "National Center for Health Statistics" state that approximately 500 in 1000 persons above 65 are affected. Numbers for Germany should be in the same range. Although a lot of research has been dedicated to these conditions many of the actual causes remain unclear. There is consensus about the involvement of Interleukin-1 in the development of rheumatoid arthritis RA. Recent results point towards a more refined understanding and a gene therapy approach utilizing synovial cells. The synovium will in this strategy be the locus of drug (eg hormone) synthesis antagonizing the rheumatoid disease. We believe that this new approach will have a major impact on the treatment of RA.

Aged↗
PubMedDate not supplied

[The interaction between synovial cytokines and peripheral nerve function: a potential element in the development of radicular syndrome].

Cytokines of rabbit synovial origin were injected into 6 rats under the epineurium of the sciatic nerve. Five controls were injected with similar preparations lacking cytokines. After injection, rats were examined for a period of 7 days. For neurophysiological evaluation the tibial branch of the sciatic nerve was stimulated with supramaximal voltage impulses of constant duration. The responses were recorded at the dorsal root entry zone L1. F-wave latencies were recorded at the distal hind paw after stimulation of the tibial nerve. Filters were set at LF: 20 Hz, HF: 10 kHz. Synovial cytokines caused a significant decrease in amplitude and increase in latencies of the recorded nerve potentials. Our results indicate that interleukin-1, which is a major component of the synovial cytokine preparation, could play an important role in degenerative spine disease through a damaging effect on nerve function. This action would explain why radiculopathy and pain can develop without signs of nerve compression. The results are also relevant to patients suffering from osteoarthritis and rheumatoid arthritis.

Animals↗
PubMedDate not supplied

[Genetic determination of bone density].

Osteoporosis is a very common disease that concerns every forth postmenopausal white woman. The loss of bone density leads to fractures, mainly to fractures of the neck of the femur. A hereditary genesis of the idiopathic osteoporosis seems to be sure. The vitamin D receptor (VDR) has an important role for the mineralisation of the bones. His allelic variants can be used for a prediction of bone density. These alleles are correlated with endonuclease restriction areas for Bsm-1, Apa-1 and Taq-1. Among these Bsm-1 has the highest incidence for prediction. In this study the allelic variants of the VDR gene correlated with the bone density of the lumbar spine (p < 0.009).

Adult↗
PubMedDate not supplied

[The effect of cytokines on regeneration results of compressed nerve roots and transsected peripheral nerves].

The possible beneficial effect of Interleukin-1 (IL-1) on nerve regeneration was studied using clinical, neurophysiological and histomorphological methods. The sciatic nerves of Wistar rats were transsected and the severed ends abutted, sewn together and covered with fibrin adhesive. In a second group the lumbar-sacral nerve roots were exposed, IL-1 was injected and compression of the nerve roots was carried out. The region surrounding the lesion was infused with either saline (controls) or IL-1 (treatment group) in both groups. Compared to the controls, the treated animals showed a significant improvement of nerve regeneration as measured by clinical and neurophysiological parameters. After 3 months of observation, the total number of myelinated axons distal to the site of lesion was increased, while the fiber diameter distribution was unchanged. It is likely that cloned IL-1 will soon become available for human treatment. The present results indicate that it may be worthwhile to investigate its usefulness in the treatment of peripheral nerve injury in primates and humans.

Animals↗