Biomedical subjects

S I Mellgren

Publications and source records attributed to S I Mellgren.

At least 19 recordsLinked to original sources

PubMed1998

[Myelin diseases affecting both the central and the peripheral nervous system].

Myelin is synthesized by oligodendrocytes in the central nervous system and by Schwann cells in the peripheral nervous system. A combined dysmyelinating/demyelinating process in the central nervous system and in the peripheral nervous system occurs only rarely. A brief review of these conditions is given in this article. Occasionally, coexistence of multiple sclerosis and chronic inflammatory demyelinating polyneuropathy is reported. Cases of multiple sclerosis, hypertrophic polyneuropathy, and central nervous system demyelination in Miller-Fisher syndrome and Guillain-Barré syndrome have also been reported. Concurrent dysmyelination in the central nervous system and peripheral nerve demyelination are common in metachromatic leukodystrophy, Krabbe disease and adrenoleukodystrophy. A Norwegian family with adult-onset demyelinating disease affecting both the peripheral and central nervous system has recently been described. The mode of inheritance is probably autosomal dominant, but its exact nature remains unknown.

Central Nervous System Diseases↗

PubMed1998

The function of sensory nerve fibers in lumbar radiculopathy. Use of quantitative sensory testing in the exploration of different populations of nerve fibers and dermatomes.

STUDY DESIGN: The function of sensory nerve fibers in patients with lumbar radiculopathy and in control individuals was evaluated using quantitative sensory testing. OBJECTIVES: To investigate the effect of lumbar nerve root compression on different populations of nerve fibers and to explore the function of sensory nerve fibers in neighboring nerve roots not involved in the mechanical compression. BACKGROUND DATA: Results from experimental and clinical studies indicate that chronic compression of lumbar nerve roots affects the large myelinated nerve fibers. The majority of nerve fibers involved in the sensation of pain, however, are small afferent nerve fibers. It is therefore of interest to study the effect of compression on large and small sensory afferent channels. Several authors have elucidated the biochemical interaction between disc tissue and nerve roots. Chemical substances in the epidural space can reach the nerve fibers in nerve roots at the same or neighboring lumbar segments. In this way, fibers not involved in the mechanical compression may be affected. METHODS: The small nerve fibers were studied using tests for thermal thresholds (thermotest), and the large myelinated fibers were studied by vibrametry. Forty-two patients were investigated in the symptomatic and the asymptomatic leg, and the results were compared with those of 21 healthy individuals. RESULTS: The thresholds of cold, warmth, and vibration were significantly increased in the dermatome of the compressed nerve root, indicating that large and small sensory nerve fibers were affected. Further, the thresholds were significantly increased in the neighboring dermatomes in the symptomatic and the asymptomatic leg. CONCLUSION: Large and small sensory afferent nerve fibers are affected in lumbar radiculopathy. The increase in sensation thresholds in the ipsilateral neighboring dermatome and in the dermatomes in the asymptomatic leg indicates that adjacent nerve roots are involved in the pathophysiology of sciatica in patients with lumbar disc herniation.

Adult↗

PubMed1998

Progressive central and peripheral demyelinating disease of adult onset in a Norwegian family.

OBJECTIVE: To describe the clinical features of a Norwegian family with a combined central and peripheral demyelinating disease. DESIGN: Multiple case report. SUBJECTS AND MATERIALS: Three generations of a Norwegian family. Medical records were available for all 9 members of the second generation and 5 affected members in the third generation. RESULTS: At least 5 members had clinical features, neuroimaging findings, and electrophysiologic signs indicating a chronic progressive disorder affecting both the central and peripheral nervous systems. The clinical symptoms developed between the ages of 30 and 70 years in affected family members, who gradually developed sensory loss, muscle deterioration, and distal weakness in all extremities, unsteady gait, and dysarthria. Five of 9 persons in the second generation had strokes and experienced mental deterioration. The initial stroke episodes were recognized between the ages of 54 and 68 years, and death occurred between the ages of 62 and 75 years. In 7 subjects, cerebrospinal fluid protein levels were increased, and in 5 agar gel electrophoresis indicated blood-brain barrier dysfunction. Seven family members had neuroimaging signs of a widespread white matter disorder. In 4 subjects, neurophysiological investigations indicated a polyneuropathy, and in 3 subjects, results from a sural nerve biopsy showed a demyelinating neuropathy. There was no evidence of co-inheritance with genetic markers of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (19p), PMP22 (17q), APP (21q), CMTX1 (Xq), or PLP (Xq). CONCLUSIONS: Progressive central and peripheral demyelinating disease seems to be a distinct type of hereditary adult-onset demyelinating disorder affecting both the peripheral and central nervous systems. Its exact nature remains unknown.

Adult↗

PubMed1998

Emotional status in systemic lupus erythematosus.

Psychological and emotional status was assessed in 36 patients with systemic lupus erythematosus (SLE) with the General Health Questionnaire-30 (GHQ-30) and Minnesota Multiphasic Personality Inventory (MMPI) questionnaires. The two tests were found to measure different aspects of psychological functioning. More than 50% of the patients could be classified as cases with mild psychiatric disturbances, according to the GHQ, and 28% had an abnormal score > 70 on the MMPI depression subscale, indicating significant depression. Emotional disturbances such as problems with social functioning, personal discomfort in social situations, and depressive mood, were frequent and associated with skin and joint abnormalities. This suggests additional etiologies for psychological dysfunction among SLE patients other than the direct central nervous system (CNS) effect of SLE.

Adult↗

PubMed1998

Recovery of sensory nerve fibres after surgical decompression in lumbar radiculopathy: use of quantitative sensory testing in the exploration of different populations of nerve fibres.

Thirty nine patients with unilateral lumbar nerve root compression at one level were examined with quantitative sensory testing immediately before microdiscectomy and at six weeks, four months, and 12 months after surgery. Twenty one healthy volunteers were used as controls. The patients were classified as having a good or a poor result at the one year follow up. The improvement of function in small unmyelinated nerve fibres came within six weeks in the patients with a good result. By contrast the improvement of function in small myelinated fibres was not found before 12 months after surgery. The function in large myelinated fibres did not improve during the observation period. The difference in the time course of the recovery between large and small nerve fibres is assumed to reflect differing severity in the damage to the fibres before surgical decompression. The preoperative warmth detection threshold reflecting the function in small unmyelinated C fibres was significantly higher in the patients with a poor result and this may indicate that damage to C fibres before surgery is a negative prognostic factor.

Adult↗

PubMed1997

The inflammatory properties of contained and noncontained lumbar disc herniation.

STUDY DESIGN: The inflammatory properties of nucleus pulposus were assessed in biopsy samples from patients who underwent surgery for lumbar disc herniation. OBJECTIVES: To investigate the inflammatory properties of the different types of disc herniation. BACKGROUND DATA: High levels of phospholipase A2 previously have been demonstrated in a small number of patients undergoing lumbar disc surgery. Phospholipase A2 is the enzyme responsible for the liberation of arachidonic acid from cell membranes at the site of inflammation and is considered to be the limiting agent in the production of prostaglandins and leukotrienes, which are powerful mediators of inflammation. Cytokines are among the many agonists inducing phospholipase A2 activation. Several reports previously have demonstrated the difference in clinical appearance of different types of lumbar disc herniation. METHODS: Thirty-seven patients undergoing surgery for lumbar disc herniation were investigated. During surgery the disc pathology of each patient was classified into one of three groups: bulging disc, contained herniation, and noncontained disc herniation. Also during surgery, biopsy samples were taken from the nucleus, immediately frozen in liquid nitrogen, and subsequently stored at -70 C until analyzed. RESULTS: No traces of interleukin-6 or tumor necrosis factor alpha were found in the biopsy samples. There was a significant difference in the levels of leukotriene B4 and thromboxane B2 in contained versus noncontained disc herniation, and the highest concentration was found in the noncontained disc herniation group. CONCLUSION: The results support the theory that inflammatory mechanisms are involved in sciatica because of lumbar disc herniation and indicate that the different types of disc herniation have different inflammatory properties.

Adult↗

PubMed1997

[Small fiber neuropathy].

A common sign of distal small fibre neuropathy is dysesthesias, especially burning sensation distally in the extremities. These symptoms are often difficult to treat with conventional analgesics. In the course of the disease, the patient may become less sensitive to pain and changes in temperature, but clinical signs may nevertheless be minor and often difficult to detect by clinical examination. Dysautonomic features are also common. Selective affection of small fibres may occur in the form of pure small fibre neuropathy, but this may also be an early manifestation of general sensorimotor polyneuropathy. Common causes are diabetes mellitus, alcoholism, and amyloidosis. Abnormalities in small diameter fibres may be detected by quantitative sensory testing of temperature and pain thresholds, and by autonomic tests. We describe four patients with polyneuropathy with a predominance of small fibre involvement.

Adult↗

PubMed1997

Human leukocyte antigen class I in polymyositis: leukocyte infiltrates, regeneration, and impulse block.

In polymyositis (PM), T-cell mediated myocytotoxicity is directed against strongly human leukocyte antigen class I positive (HLA-I+) muscle fibers. Fiber regeneration probably is partly responsible for this HLA-I up-regulation. We have evaluated regeneration, denervation/impulse blockade, and focal leukocyte infiltrates as possible HLA-I inducing factors in PM. Distinctive patterns of HLA-I, nerve cell adhesion molecule (NCAM), and vimentin expression accompany denervation and regeneration. Regenerating fibers also have centralized nuclei. Using semiquantitative methods, we examined strongly HLA-I+ fibers in PM muscle biopsies for these markers. Sarcoplasmic HLA-I levels were related to the presence of leukocyte infiltrates and invasion of fibers. Strongly HLA-I+ fibers were frequently invaded, and regeneration-associated changes were usually observed at sites of fiber damage. Sarcoplasmic HLA-I levels were stable along intact fibers, also adjacent to leukocyte infiltrates. A majority of the strongly HLA-I+ fibers were nonregenerating (NCAM+ only). Though other mechanisms cannot be excluded, this suggests that impulse blockade or denervation may contribute to extra HLA-I up-regulation in these fibers.

Aged↗

PubMed1997

No association between peridural scar and outcome after lumbar microdiscectomy.

The association between postoperative scar formation on MRI and outcome was investigated in 54 out of one hundred patients operated on with microdiscectomy in a prospective cohort study with a one year follow up. The patients were classified as failures or successes at the 12 months follow up according to a clinical overall score. All the 14 failures were investigated with MRI, and 40 patients classified as successes were picked at random for MRI. Patients with signs of recurrent disc herniation on MRI were excluded. The MRI scans were rated according to the presence or absence of scar formation within the spinal canal and the degree of scar enhancement by two independent neuroradiologists ignorant of treatment outcome. No evidence of scar formation was found in 4 patients, a small amount in 11, intermediate in 38 and extensive scar tissue in 1 patient. Slightly enhancing scar tissue was found in 18 patients, intermediate in 27 patients and strong enhancement in 5 patients. No association between the amount or enhancement of peridural scar formation and clinical outcome was found. Both the total clinical score and the difference between pre- and post-operative clinical score were used in the calculations. Testing the different subsets in the clinical overall score, as well as the patient satisfaction VAS score, did not reveal any association.

Adult↗

PubMed1997

The rheumatoid wrist: bilateral MR analysis of the distribution of rheumatoid lesions in axial plan in a female population.

In this case-control study, we analyzed 146 wrists: a) to search for the distribution pattern of the rheumatoid lesions and, b) to correlate the distribution pattern of these lesions with the clinical parameters. Thirty-one patients with rheumatoid arthritis (RA) and 42 controls-all women-were examined by means of a bilateral MR fast field echo (FFE) sequence, in axial plan. The wrist was divided into three regions: metacarpal (level I), carpal (level II) and radioulnar (level III). Erosions were present in thirty (97%) patients and in six (14%) controls. They were asymmetrically distributed at all levels, mainly at level II. Marrow infiltration and bone destruction were seen in 35% of the patients in an asymmetrical pattern at level I and II, respectively. These lesions were absent in the control group. Subchondral cysts were asymmetrically present in both groups-in 48% of the patients at levels II and III, and in 11% of the controls at level II. In the patient group, this asymmetrical pattern of the lesions correlated with the disease duration at levels I and II (p = 0.011 and p = 0.013, respectively). Most lesions were found at the radial force-bearing column of the wrist, more in the right side. Synovial hypertrophy and hyperintense median nerve were evident in 96% and 70% of the patients, respectively. We concluded that contrary to common belief rheumatoid damages to the carpal bones become rather asymmetrical as the disease progresses. The line of force along the radial side of the wrist possibly influences the distribution pattern of the rheumatoid lesions.

Adult↗

PubMed1997

Quantitative MRI and electrophysiology of preoperative carpal tunnel syndrome in a female population.

The tunnel size is reported to play a role in median neuropathy. The aim of the study was to quantify the volume of the carpal tunnel in a selected population with idiopathic carpal tunnel syndrome (CTS), as the narrowest point of the canal was noted. Twenty-seven patients with CTS and 28 asymptomatic controls were examined. All participants were women. Both groups underwent nerve conduction studies and magnetic resonance (MR) of the wrists. On the MR axial images, the volume of carpal tunnels, the wrists and the thenar muscles were calculated bilaterally in all subjects. The values for the signal intensity of the median nerve from all wrists were also quantified and correlated with the neurophysiological findings. The carpal tunnel volume (CTV) and the wrist volume (WV)/CTV ratio were almost identical in both groups (p = 0.36 and p = 0.45, respectively). The focal narrowest point of the tunnel was similarly located in both populations, and detected at its distal third, about 8 mm from the outlet. The median nerve in the patients emitted a higher signal compared with the controls, p = 0.037. Between the two groups, there were differences in the amplitude and the distal latency of the median sensory branch (p = 0.0001 and p = 0.0001, respectively), as well as in the amplitude and the F-wave latencies of the median motor branch (p = 0.045 and p = 0.017, respectively). There was no difference in the size of the carpal tunnel in women with idiopathic CTS compared with healthy controls, as the focal narrowest point was equally located in both groups near the canal outlet.

Adolescent↗

PubMed1997

Nigro-striatal degeneration demonstrated in parkinsonian patients with iodine-123-beta-CIT SPECT: methods of quantitation.

Single photon emission computed tomography (SPECT) images were obtained in 3 healthy volunteers and 7 parkinsonian patients 22 h after injection of 120 MBq iodine-123-beta-CIT. There was a high radioactivity in the striatal region against a uniform background in the volunteers but pronouncedly reduced striatal activity in the patients. Total striatal activity in each hemisphere of each individual was calculated as the sum of all activity in excess of the background in all reconstructed images. There was a high correlation between reduction of striatal activity and motor scores in the unified rating scale for parkinsonism (URSP) for the patients. A method developed for calculation of the activity distribution along the length axis of the striatum indicated a more pronounced degeneration in the putamen compared with the caudate nucleus in the patients. Iodine-123-beta-CIT SPECT appears to be a good quantitative method for nigro-striatal degeneration in parkinsonian patients.

Aged↗

PubMed1997

Bilateral fast magnetic resonance imaging of the operated carpal tunnel.

Our aim was to quantify the structural changes of the carpal tunnel including area and volume after surgical release. We studied 28 patients who underwent 31 operations for carpal tunnel syndrome (CTS), mean age 54.7 years (range 32-78). All had abnormal nerve conduction studies. Magnetic resonance imaging (MRI) of both wrists was done before and after operation using two fast imaging sequences, turbo spin echo (TSE) and fast field echo (FFE). The same surface coils and parameters were used in both instances. With a computerised analyser we calculated the volume of the whole tunnel from inlet to outlet before and after operation and the wrist volume:carpal tunnel volume ratio. The intensity of the magnetic resonance signal emitted by the median nerve was assessed in all wrists before and after operation. The mean (SD) volume of the tunnel in 31 wrists with CTS was 11511.7 (2857) mm3 before and 13803.4 (3034.9) mm3 after operation (p = 0.0001). The mean (SD) relative signal intensity of the median nerve was 1.7 (1.8) preoperatively and 1.3 (1.1) postoperatively (p = 0.19). Other postoperative changes included persistent nerve enlargement (n = 21), misalignment of the tendons (n = 20), fibrous tissue deposits (n = 20), fat tissue deposits (n = 21), and muscle oedema (n = 6). The modifications of the carpal canal as a consequence of open surgical release (including increased volume and displacement of the flexor tendons) argue for the use of an endoscopic procedure in the treatment of CTS.

Adult↗

PubMed1996

Bilateral fast MR imaging of the rheumatoid wrist.

To evaluate the structural changes in the carpal tunnel and possible intrinsic median nerve damages in RA patients, quantitative bilateral magnetic resonance imaging (MRI) of the wrists was performed by means of a fast imaging sequence. Thirty-three women with RA and 42 controls were examined. The length of the carpal tunnel, the carpal tunnel volume/wrist volume (CTV/WV) ratio and the signal intensity of the nerve were calculated in both groups, bilaterally. The CTV/WV ratio was 0.12 in the patients and 0.11 in the control group (p = 0.007). A negative association was found between disease duration and carpal tunnel volume/wrist volume ratio (p = 0.049). Mean distal latency in the right motor median nerve was 3.0 +/- 0.4 msec (patients) and 3.4 +/- 0.6 msec (controls) (p = 0.002). Mean values in the right sensory branch were 1.2 +/- 0.1 msec (patients) and 1.4 +/- 0.3 (controls) (p = 0.01). The lack of association between the size of the carpal canal and neurophysiological parameters found in this study may suggest a possible protection of the median nerve by the increased canal size in patients with RA.

Adult↗

PubMed1996

MRI of anatomical variants of the wrist in women.

In the analysis of magnetic resonance (MR) images of the wrist joint, some structural variations may lead to misinterpretation. Our aim was to search for different anatomical variants and their MR characteristics on axial images. Two groups of patients with rheumatoid arthritis (thirty one) and carpal tunnel syndrome (sixty two), and a group of asymptomatic controls (fifty four) underwent bilateral MR axial wrist imaging from the metacarpal bases to the distal radiocarpal joint. The imaging techniques included spin echo (SE), turbo spin echo (TSE) and fast field echo (FFE) sequences, using 3 mm-slice thickness. Different anatomical variants including hypoplasia of the hamulus or hook of the hamate bone (4 cases), anomalous muscles (lumbricals) inside the carpal tunnel (2 cases), unusual location (5 cases) and double branching of the median nerve (14 cases), and aberrant median artery (one case) were detected. These variants, if unfamiliar to MR readers, may be misinterpreted as pathological features.

Adolescent↗

PubMed1996

Quantified neurological examination with emphasis on motor and sensory functions in patients with rheumatoid arthritis and controls.

A controlled study of quantified clinical neurological examination, including psychophysical assessment of sensory thresholds, in patients with rheumatoid arthritis (RA) was carried out. Fifty-five women with seropositive RA living in North Norway and 83 healthy controls underwent clinical neurological examination quantified by neurological symptom score (NSS) and neurological deficit score (NDS). Vibration threshold (VT), warm-cold detection threshold (limen) as well as heat pain detection threshold (HPDT) were performed to evaluate afferent myelinated and unmyelinated fibre functions. Higher scores on NSS and NDS were seen in RA patients compared with the controls. Higher index finger and big toe VT was demonstrated in the patients, while results from warm-cold limen and HPDT were not significantly different in the two groups. Among the disease-related variables, the most prominent finding was a positive association of index finger VT with disease duration in the patients (P = 0.01). Maximum walking time (15 m) was a significant predictor of big toe VT in the patient group (P = 0.0001). This study suggests impaired peripheral nerve function in afferent myelinated fibres. However, involvement of dorsal column fibres cannot be excluded, although patients with radiological atlantoaxial subluxation were not included in this study.

Adolescent↗

PubMed1996

Quantitative cerebral MRI in epileptic patients.

OBJECTIVES: To determine cerebral atrophy parameters on MRI images of epileptic patients. MATERIAL AND METHODS: Examination of the brain was performed in a 0.5 Tesla magnet in 32 women with epilepsy and 36 female healthy controls. Fifteen patients were classified to have generalised epilepsy and 17 had partial seizure onset. Epileptic patients with structural brain changes were excluded. At midsagittal level the area of corpus callosum, cerebrum and cerebellum were selected as atrophy parameters. At transverse level the ventricle-brain ratio (VBR) as a measure of overall cerebral atrophy, bifrontal ratio (BFR) reflecting atrophy in the area of the frontal horns, bicaudate ratio (BCR) and bioccipital ratio (BOR) were calculated to evaluate atrophy in the region of nucleus caudatus as well as in the occipital area. RESULTS: The mean values of VBR were significantly larger in the two epileptic groups than in controls, p = 0.0003. No significant difference in mean VBR were found between focal and generalised seizure onset epilepsy. Also significant decreased cerebellar area on midsagittal section was detected in epileptic patients with partial onset epilepsy compared with controls, p = 0.037. Atrophy was not associated with type and duration of epilepsy, but VBR and age were positively associated in patients with generalised onset seizures. CONCLUSION: These findings suggest general brain atrophy to be present in epileptic patients including those with partial epilepsy. Whether atrophy in epileptic patients occurs as a consequence of disease-related factors like hypoxia or treatment with antiepileptic drugs has to be investigated in a prospectively designed study.

Adult↗

PubMed1996

Recovery of sensory function after surgical decompression in carpal tunnel syndrome.

The function of thick and thin sensory nerve fibers after surgical decompression in carpal tunnel syndrome were evaluated using quantitative sensory testing (QST). The thin nerve fibers were studied using tests for thermal thresholds, and the thick myelinated fibers by vibrametry. The tests were performed before surgery and at 6 weeks, 4 and 10 months after surgery. The improvement of function in thin nerve fibers came within 6 weeks (P = 0.001). The improvement of function in thick myelinated fibers continued to improve until 4 months after the operation (P = 0.0001). This difference in the time course of the recovery indicates that the thick myelinated nerve fibers were more affected than the thin nerve fibers. The function of both type sensory nerve fibers did also improve in the fifth finger (P = 0.05). The function in thin nerve fibers worsened somewhat between 6 weeks and 4 months after surgery, possibly due to postoperative scar tissue.

Adult↗