Biomedical subjects

M Zanetti

Publications and source records attributed to M Zanetti.

At least 37 records · Page 2Linked to original sources

PubMed2001

Therapeutic efficacy of selective nerve root blocks in the treatment of lumbar radicular leg pain.

The objective of this study was to investigate the clinical effectiveness of nerve root blocks (i.e., periradicular injection of bupivacaine and triamcinolone) for lumbar monoradiculopathy in patients with a mild neurological deficit. We have retrospectively analysed 30 patients (29-82 years) with a minor sensory/motor deficit and an unequivocal MRI finding (20 disc herniations, 10 foraminal stenoses) treated with a selective nerve root block. Based on the clinical and imaging findings, surgery (decompression of the nerve root) was justifiable in all cases. Twenty-six patients (87%) had rapid (1-4 days) and substantial regression of pain, five required a repeat injection. 60% of the patients with disc herniation or foraminal stenosis had permanent resolution of pain, so that an operation was avoided over an average of 16 months (6-23 months) follow-up. Nerve root blocks are very effective in the non-operative treatment of minor monoradiculopathy and should be recommended as the initial treatment of choice for this condition.

Adult↗

PubMed2001

MR arthrographic variability of the arthroscopically normal glenoid labrum: qualitative and quantitative assessment.

The purpose of this study was to assess qualitatively and quantitatively the MR arthrographic variability of the arthroscopically normal glenoid labrum. Form and signal abnormalities of arthroscopically normal labral parts were analyzed on axial and coronal MR arthrograms of 55 consecutive patients (mean age 43.8 years, age range 21-76 years) referred mainly for suspected rotator cuff lesions. Length and width of the labrum were measured. One hundred twenty-one of 241 (50%) arthroscopically normal labral parts demonstrated normal (low) signal intensity and normal form on MR arthrograms. Increased linear or globular signal intensity was present in 74 of 241 (31%) normal labral parts, deformed or fragmented labra in 28 (12%), complete separation of the labrum from the glenoid in 4 (2%), a cleft in 5 (2%), attenuation in 4 (2%), and complete absence in 5 (2%), respectively. The mean size of the normal labrum varied between 3.8 x 3.3 mm at the subscapularis bursa level (anteriorly) and 6.1 x 5.6 mm at the inferior portion of the glenoid (anteriorly). The size was not significantly different between arthroscopically normal and abnormal labral parts (p = 0.13-0.83). Since the MR appearance of the arthroscopically normal glenoid labrum varies considerably concerning signal intensity, form, and size, only major tears or detachments of the labrum should be diagnosed.

Adult↗

PubMed2001

Insulin infusion normalizes fasting and post-prandial albumin and fibrinogen synthesis in Type 1 diabetes mellitus.

AIMS: The effect of metabolic control on hepatic synthesis of plasma proteins in Type 1 diabetes mellitus (T1DM), in the post-absorptive and post-prandial state, is not known. METHODS: We measured fractional synthetic rates (FSR) of albumin and fibrinogen in six insulin-infused T1DM patients and in five to nine control subjects, before and for approx. 4 h after a mixed liquid meal. Phenylalanine tracer precursor/product relationships and steady-state conditions were used. In the post-absorptive state, patients were studied in near euglycaemic conditions after an overnight intravenous insulin infusion. During the meal (approx. 11 kcal/kg), the insulin infusion rate was increased to maintain plasma glucose concentrations below approx. 10 mmol/l. RESULTS: Post-absorptive FSR of albumin (5.7 +/- 0.6%/day) and fibrinogen (11.3 +/- 0.6%/day) in T1DM were similar to control values (6.4 +/- 0.9 and 13.1 +/- 1.1, respectively). After the meal, albumin FSR increased (P = 0.0032 by anova) in both groups (T1DM, to 14.4 +/- 2.7%/day; controls, to 18.2 +/- 3.7%/day). Fibrinogen FSR also increased (P = 0.0048 by anova) in both the T1DM (to 18.2 +/- 2.6) and the control subjects (to 27.3 +/- 6.2). There was no difference between T1DM and control subjects in the post-prandial FSR of both proteins. CONCLUSIONS: Albumin and fibrinogen FSR in T1DM can be maintained within near-normal ranges by insulin infusion under post-absorptive and post-prandial conditions.

Adult↗

PubMed2001

Anti-microbial activity and cell binding are controlled by sequence determinants in the anti-microbial peptide PR-39.

PR-39 is a member of the proline-rich group of cathelicidin peptides, a class of anti-microbial peptides found in skin and in leukocytes. In addition to their innate defense function, these proline-rich peptides influence a number of mammalian cell processes, including inflammation, development, differentiation, and metastatic transformation. To characterize the mechanism further, through which proline-rich cathelicidin peptides may exert their numerous effects, we altered various conserved peptide sequence motifs using a biologically active fragment of PR-39 [PR-39(15)] as the template: We altered the N-terminal charge of its SH3 binding motif, substituted tryptophan for a conserved intervening leucine, and modified a proline-arginine stretch (residues 10-13). These peptide variants were tested for binding known targets of PR-39 and for biologic activity in mammalian and bacterial systems. We found that the N-terminal arginines are crucial for protein binding and that modification in this domain results in loss of affinity and specificity in binding to generalized and SH3-containing targets. The N-terminal charged residues are also required for NIH 3T3 syndecan induction and anti-microbial activity. In addition, modification of more C-terminal residues eliminates anti-bacterial activity while having less of an effect on peptide interactions in mammalian cell assays. This study shows that the presence of a charged N-terminus is important for peptide activity in both mammalian and bacterial systems whereas the C-terminal alterations of PR-39(15) more definitively affect anti-bacterial activity.

3T3 Cells↗

PubMed2001

Structural and functional analysis of horse cathelicidin peptides.

Cathelicidin-derived antimicrobial peptides are a component of the peptide-based host defense of neutrophils and epithelia, with a widespread distribution in mammals. We recently reported the cDNA sequences of three putative horse myeloid cathelicidins, named eCATH-1, -2, and -3. A Western analysis was performed to investigate their presence in neutrophils and processing to mature peptides. eCATH-2 and eCATH-3, but not eCATH-1, were found to be present in uncleaved forms in horse neutrophils. The corresponding mature peptides were detected in inflammatory sites, suggesting that processing of the propeptides takes place upon neutrophil activation. A functional characterization was then performed with synthetic eCATH peptides. Circular dichroism measurements indicated an amphipathic alpha-helical conformation of these peptides in an anisotropic environment, and in vitro assays revealed a potent activity and a broad spectrum of antimicrobial activity for eCATH-1 and a somewhat more restricted spectrum of activity for eCATH-2. Conversely, a strong dependence on salt concentration was observed when the activity of eCATH-3 was tested. This peptide efficiently killed bacteria and some fungal species, i.e., Cryptococcus neoformans and Rhodotorula rubra, in low-ionic-strength media, but the activity was inhibited in the presence of physiological salt medium. This behavior could be modified by modulating the amphipathicity of the molecule. In fact, the synthetic analogue LLK-eCATH-3, with a slightly modified sequence that increases the hydrophobic moment of the peptide, displayed a potent activity in physiological salt medium against the strains resistant to eCATH-3 under these conditions.

Animals↗

PubMed2001

Surveillance programme of cirrhotic patients for early diagnosis and treatment of hepatocellular carcinoma: a cost effectiveness analysis.

BACKGROUND: Hepatocellular carcinoma (HCC) is a major cause of death in cirrhotic patients. This neoplasm is associated with liver cirrhosis (LC) in more than 90% of cases. Early diagnosis and treatment of HCC are expected to improve survival of patients. AIMS: To assess the cost effectiveness of a surveillance programme of patients with LC for the early diagnosis and treatment of HCC. PATIENTS: A cohort of 313 Italian patients with LC were enrolled in the surveillance programme between March 1989 and November 1991. In the same period, 104 consecutive patients with incidentally detected HCC were referred to our centre and served as a control group. METHODS: Surveillance was based on ultrasonography (US) and alpha fetoprotein (AFP) determinations repeated at six month intervals. Risk factors for HCC were assessed by multivariate analysis (Cox model). Outcome measures analysed were: (1) number and size of tumours; (2) eligibility for treatment; and (3) survival of patients. Economic issues were: (1) overall cost of surveillance programme; (2) cost per treatable HCC; and (3) cost per year of life saved (if any). Costs were assessed according to charges for procedures at our university hospital. RESULTS: Surveillance lasted a mean of 56 (31) months (range 6-100). During the follow up, 61 patients (19.5%) developed HCC (unifocal at US in 49 cases), with an incidence of 4.1% per year of follow up. AFP, Child-Pugh classes B and C, and male sex were detected as independent risk factors for developing HCC. Only 42 (68.9%) of 61 liver tumours were treated by surgical resection, orthotopic liver transplantation, or local therapy. The cumulative survival rate of the 61 patients with liver tumours detected in the surveillance programme was significantly longer than that of controls (p=0.02) and multivariate analysis showed an association between surveillance and survival. The overall cost of the surveillance programme was US$753 226, the cost per treatable HCC was US$17 934, and the cost for year of life saved was US$112 993. CONCLUSION: Our surveillance policy of patients with LC requires a large number of resources and offers little benefit in terms of patient survival. The decision whether to adopt a surveillance policy towards HCC should rely on the prevalence of the disease in the population and on the resources of a particular country.

Adult↗

PubMed2001

Palmar tilt of the distal radius: influence of off-lateral projection initial observations.

PURPOSE: To evaluate the effect of slight off-lateral positioning of the wrist on measurements of the palmar tilt of the distal radius on lateral views and to determine how this effect can be corrected quantitatively. MATERIALS AND METHODS: Seven cadaveric forearms in neutral and various oblique positions (5 degrees, 10 degrees, 15 degrees, 20 degrees ) of supination and pronation were examined with lateral radiography. The palmar tilt of the distal radius measured on the radiographs was correlated with each position of the wrist and the distance between the position of the palmar cortex of the pisiform bone (P) and a reference point (point 0), which was defined as the midpoint within the interval between palmar cortices of the distal scaphoid pole and of the capitate head (P0 distance). The same measurements were performed on 11 wrists during arthrography. RESULTS: The apparent palmar tilt of the distal radius increased with supination of the forearm. Regression analysis with the P0 distance as independent and palmar tilt as dependent variables resulted in a slope of 0.95 in the seven cadaveric wrists and of 0.92 in the 11 wrist arthrograms. The squares of the correlation coefficients (R(2)) were 0.89 in cadaveric wrists and 0.69 in 11 wrist arthrograms. CONCLUSION: Differences in the palmar tilt produced by off-lateral projections of the wrist can be estimated from the measured difference of the P0 distance. A 1-mm difference in the P0 distance corresponds to a difference in the palmar tilt of approximately 1 degrees.

Adult↗

PubMed2001

Selective nerve root blocks for the treatment of sciatica: evaluation of injection site and effectiveness--a study with patients and cadavers.

PURPOSE: To relate different types of radiographic contrast material distributions to anatomic compartments by using cadaveric specimens and to relate the injection site to treatment-induced discomfort and therapeutic effect. MATERIALS AND METHODS: The contrast material distributions of selective nerve root blocks (SNRBs) in 36 patients (13 women, 23 men; mean age, 52 years; age range, 22-88 years) were graded by two radiologists in conference as type 1 (tubular appearance), type 2 (nerve root visible as filling defect), or type 3 (nerve root not visible). These patterns were correlated with pain reduction after 15 minutes and 2 weeks (with a visual analogue scale of 100-mm length). In addition, 30 nerve roots were injected with iodine-containing contrast material and blue dye in three cadaveric specimens. Radiographs were compared with anatomic sections. RESULTS: After 15 minutes and 2 weeks, 75% and 86% of the patients, respectively, reported pain relief. Mean pain relief length after 15 minutes for type 1 distribution was 60 mm; for type 2, 44 mm; and for type 3, 22 mm; and after 2 weeks, it was 34 mm for type 1, 31 mm for type 2, and 57 mm for type 3. There was no correlation between early and late response. Pain during intervention was less pronounced in type 2 injection, compared with type 1 (P = .002). On the basis of anatomic sections, type 1 injection was intraepineural; type 2, extraepineural; and type 3, paraneural. CONCLUSION: Therapeutic SNRB is effective in sciatica, but early response does not predict the effect after 2 weeks. Type 1 injections are more painful than type 2 injections.

Adult↗

PubMed2001

Patient's assessment of discomfort during MR arthrography of the shoulder.

PURPOSE: To assess patient discomfort during (a) intraarticular contrast material injection (arthrography) and (b) magnetic resonance (MR) imaging in patients referred for MR arthrography of the shoulder and to compare the relative discomfort associated with each part of the examination. MATERIALS AND METHODS: With use of a visual analogue scale (VAS) and relative ratings, 202 consecutive patients referred for MR arthrography of the shoulder rated the expected discomfort and that actually experienced during both arthrography and MR imaging. The Student t test was used for statistical analysis. RESULTS: The average VAS score (0 = "did not feel anything," 100 = "unbearable") was 16.1 +/- 16.4 (SD) for arthrography and 20.2 +/- 25.0 for MR imaging. This difference was statistically significant (P =.036, paired t test). The discomfort experienced during arthrography was as expected in 90 (44.6%) patients, less than expected in 110 (54.4%), and worse than expected in two (1.0%). MR imaging-related discomfort was as expected in 114 (56.4%) patients, less than expected in 66 (32.7%), and worse in 22 (10.9%). Arthrography was rated worse than MR imaging by 53 (26.2%) patients, equal to MR imaging by 69 (34.2%), and less uncomfortable than MR imaging by 80 (39.6%). CONCLUSION: Arthrography-related discomfort was well tolerated, often less severe than anticipated, and rated less severe than MR imaging-related discomfort.

Adolescent↗

PubMed2001

MR morphology of alar ligaments and occipitoatlantoaxial joints: study in 50 asymptomatic subjects.

PURPOSE: To assess the magnetic resonance (MR) imaging appearance of the alar ligaments and joints in the upper cervical spine to determine the prevalence of structural alterations in asymptomatic individuals. MATERIALS AND METHODS: Fifty healthy individuals (31 men, 19 women) with a mean age of 30 years (range, 19-47 years) underwent coronal T1- and T2-weighted and transverse T1-weighted MR imaging. MR findings were analyzed independently by two musculoskeletal radiologists, with disagreements resolved in conference. RESULTS: Alar ligaments were detected in 42 (84%) (left side) and 38 (76%) (right side) of 50 individuals. The majority of ligaments (88%) and joints (58%) of the craniocervical junction (CCJ) were asymmetric. Asymmetry of the joint between C1 and C2 was less frequent (46%). Small amounts of fluid were detected in 8% of CCJ joints and 56% of C1-C2 joints in asymptomatic individuals. CONCLUSION: Asymmetry of alar ligaments, CCJ and C1-C2 facet joints, and joint effusions are common in asymptomatic individuals. The clinical relevance of these MR findings is therefore limited in the identification of the source of neck pain in symptomatic patients.

Adult↗

PubMed2001

Painful Lumbar Disk Derangement: Relevance of Endplate Abnormalities at MR Imaging.

PURPOSE: To investigate the predictive value of magnetic resonance (MR) imaging of abnormalities of the lumbar intervertebral disks, particularly with adjacent endplate changes, to predict symptomatic disk derangement, with discography as the standard. MATERIALS AND METHODS: Fifty patients aged 28-50 years with chronic low back pain and without radicular leg pain underwent prospective clinical examination and sagittal T1- and T2-weighted and transverse T2-weighted MR imaging. Subsequently, patients underwent lumbar discography with a pain provocation test (116 disks). MR images were evaluated for disk degeneration, a high-signal-intensity zone, and endplate abnormalities. Results of pain provocation at discography were rated independently of the image findings as concordant or as nonconcordant or painless. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated to assess the clinical relevance of MR abnormalities. RESULTS: Normal disks on MR images were generally not painful at provocative discography (NPV, 98%). Disk degeneration (sensitivity, 98%; specificity, 59%; PPV, 63%) and a high-signal-intensity zone (sensitivity, 27%; specificity, 85%; PPV, 56%) were not helpful in the identification of symptomatic disk derangement. When only moderate and severe type I and type II endplate abnormalities were considered abnormal, all injected disks caused concordant pain with provocation (sensitivity, 38%; specificity, 100%; PPV, 100%). CONCLUSION: Moderate and severe endplate abnormalities appear be useful in the prediction of painful disk derangement in patients with symptomatic low back pain.

Adult↗

PubMed2001

MR arthrography of the glenohumeral joint: two concentrations of gadoteridol versus Ringer solution as the intraarticular contrast material.

PURPOSE: To compare two concentrations of gadoteridol with Ringer solution as the contrast material for magnetic resonance (MR) arthrography of the glenohumeral joint. MATERIALS AND METHODS: One hundred fifty-six consecutive MR arthrograms were randomly obtained with either 2 mmol/L gadoteridol (n = 52), 4 mmol/L gadoteridol (n = 52), or Ringer solution (n = 52). MR arthrograms were assessed quantitatively (for contrast-to-noise ratio [CNR]) and qualitatively (for overall image quality, image contrast, degree of joint distention, and motion artifacts). MR diagnoses were compared with arthroscopic or surgical reports in 88 patients. RESULTS: The mean CNR at imaging was 40.4 with 2 mmol/L gadoteridol, 45.6 with 4 mmol/L gadoteridol, and 48.7 with Ringer solution. The CNR with 2 mmol/L gadoteridol was significantly lower than that with 4 mmol/L gadoteridol (P =.025) and Ringer solution (P =.012). Qualitative differences between the two gadoteridol concentrations were not significant. Ringer solution was significantly worse with regard to overall quality, motion artifacts, image contrast, and joint distention compared with both gadoteridol concentrations. Ringer solution was slightly more sensitive and less specific than the gadoteridol solutions in the detection of supraspinatus tears and less sensitive and more specific in enabling diagnosis of superior labrum anteroposterior lesions. CONCLUSION: MR arthrograms of the shoulder obtained with gadoteridol and those obtained with Ringer solution provided equivalent diagnostic accuracy. The authors, however, preferred the image quality of the gadoteridol-enhanced arthrograms.

Adolescent↗

PubMed2001

Plasma protein synthesis in patients with low-grade nephrotic proteinuria.

Overt nephrotic syndrome is characterized by albumin and fibrinogen hyperproduction and reduced very low density lipoprotein apolipoprotein B-100 (VLDL apoB-100) clearance. Whether similar changes also occur in low-grade proteinuria is not known. Thus we measured albumin, fibrinogen, and VLDL apoB-100 kinetics in six patients with modest proteinuria and normal creatinine clearance (P) and in ten control subjects (C) by leucine tracer infusion and precursor-product relationships. In P, plasma albumin concentration was decreased (P < 0.003), whereas concentrations of fibrinogen and VLDL apoB-100 were increased (P < 0.001). In P, albumin fractional secretion rate (FSR) was increased (P < 0.01), fibrinogen FSR was normal, and VLDL apoB-100 FSR was decreased (P < 0.03). As a result, in P, absolute secretion rates (ASR) of albumin and fibrinogen were increased (P < 0.03), whereas VLDL apoB-100 ASR was normal. Albumin FSR was inversely correlated to oncotic pressure in P but not in C. These findings suggest that low-grade nephrotic proteinuria is characterized by simultaneous multiple alterations in turnover rates of albumin, fibrinogen, and VLDL apoB-100. Their pathogenesis, however, appears to be multifactorial.

Adult↗

PubMed2001

Gene transfer of superoxide dismutase isoforms reverses endothelial dysfunction in diabetic rabbit aorta.

Increased production of oxygen free radicals is an important mechanism of endothelial dysfunction in diabetes mellitus. Our goal was to test whether adenovirus (Ad)-mediated gene transfer of copper/zinc (CuZn) or manganese superoxide dismutase (Mn SOD) improves relaxation of diabetic vessels. The aortas from 9 alloxan-induced diabetic mellitus (DM) and 16 control rabbits were used. Control and DM rings were transduced ex vivo with Ad vectors encoding Mn SOD (AdMn SOD), CuZn SOD (AdCuZn SOD), beta-galactosidase (Ad(beta)gal), or diluents. In the absence of gene transfer, SOD activity was significantly increased in DM aortas. Transgene expression in DM AdCuZn SOD and DM AdMn SOD-transduced vessels was confirmed by Western blot analysis and by increased SOD activity (DM AdCuZn SOD, 76.2 +/- 9.3; DM AdMn SOD, 65.2 +/- 4.8; P < 0.05 vs. DM Ad(beta)gal; 50.9 +/- 4.4 U/mg protein). Superoxide production was increased in DM Ad(beta)gal-transduced aorta and relaxations to acetylcholine were impaired in these vessels. Gene transfer of CuZn SOD and Mn SOD corrected both of these defects. Thus Ad-mediated gene transfer CuZn and Mn SOD to the diabetic aorta improves endothelium-dependent relaxation.

Acetylcholine↗

PubMed2001

Superoxide anions and endothelial cell proliferation in normoglycemia and hyperglycemia.

-Oxygen free radicals are believed to play a key role in cellular proliferation, and increased concentrations of these molecules have been implicated in the pathogenesis of endothelial dysfunction in diabetes mellitus. Our aim was to study the role of superoxide anions in endothelial cell proliferation under conditions of normoglycemia and hyperglycemia. Human aortic endothelial cells (HAECs) and human umbilical vein endothelial cells (HUVECs) exposed to adenoviral vectors encoding CuZnSOD (AdCuZnSOD), ss-galactosidase (Adssgal), or diluent (control) were cultured in normal glucose (NG, 5.5 mmol/L) or high glucose (HG, 28 mmol/L) medium. Cell proliferation was compared by use of [(3)H]thymidine incorporation and cell count in transduced and control cells in the setting of NG and HG. Transgene expression was detected in transduced cells by X-gal staining and by Western analysis and SOD activity assay in AdCuZnSOD-transduced cells. Superoxide production was significantly (P:<0.05) decreased in AdCuZnSOD-transduced cells cultured in both NG and HG medium. In NG, AdCuZnSOD-transduced endothelial cells had decreased proliferation compared with control cells. After 48 hours in HG, superoxide levels were increased and DNA synthesis was decreased (P:<0.05) in control and Adssgal-transduced but were not affected in AdCuZnSOD-transduced cells. In addition, after 7 days in HG, cell counts were reduced (P:<0.05) in control (73+/-2.5%) and Adssgal-transduced (75+/-3.4%) but not in AdCuZnSOD-transduced cells (89+/-3.4%). These results suggest that either a deficiency or an excess of superoxide anions inhibits endothelial cell proliferation, and the inhibitory effect of increased superoxide due to hyperglycemia can be reversed by CuZnSOD overexpression.

Anions↗

PubMed2001

Studies on CD4 T cell immunity using somatic transgene immunization.

This review presents and discusses our recent data on the use of somatic transgene immunization in the induction of CD4 T cell responses in vivo. Somatic transgene immunization is a process that targets B lymphocytes resident in the spleen with DNA coding for antigenized immunoglobulin H chain genes. After transgenesis B lymphocytes function as antigen-producing and antigen-presenting cells. The studies reviewed herein describe the characteristics of the primary and memory CD4 response against a dominant Th cell determinant. In addition, they show how ad hoc modifications of the transgene result in the induction of a CD4 T cell response against Th cell determinants against which a response is normally not obtained. The new concept Th-Th cooperation is discussed.

Amino Acid Sequence↗

PubMed2000

Functional cooperation between T helper cell determinants.

The immune response to T helper (Th) cell determinants of a variety of antigens is often poor and limits severely the potential efficacy of current therapeutic measures through vaccination. Here, we report that an immunologically silent tumor determinant can be rendered immunogenic if linked with a dominant determinant of a parasite antigen, suggesting the existence of functional Th-Th cooperation in vivo. This phenomenon could be mimicked in part by signaling either through CD40 to the antigen-presenting cells or through OX40 to the tumor-determinant reactive T cells, with maximal effects obtained by combined anti-CD40 and anti-OX40 treatment in vivo. The data suggest that CD4 T cells reactive with a dominant determinant provide help to other CD4 T cells through up-regulating the costimulatory ability of antigen-presenting cells, in much the same way as help for CD8 cells. CD4 help for CD4 T cells represents a new immunological principle and offers new practical solutions for vaccine therapy against cancer and other diseases in which antigenic help is limiting.

Amino Acid Sequence↗

PubMed2000

Natural history of individuals with asymptomatic disc abnormalities in magnetic resonance imaging: predictors of low back pain-related medical consultation and work incapacity.

STUDY DESIGN: Prospective study on individuals with asymptomatic lumbar disc abnormalities detected in magnetic resonance imaging. OBJECTIVES: To determine the natural history of asymptomatic disc abnormalities in magnetic resonance imaging and to identify predictors of future low back pain-related medical consultation and work incapacity. SUMMARY OF BACKGROUND DATA: The natural history of individuals with asymptomatic disc herniations has not been well established, but the high rate of lumbar disc alterations recently detected in asymptomatic individuals by magnetic resonance imaging demands reconsideration of a pathomorphology-based explanation of low back pain and sciatica. METHODS: Forty-six asymptomatic individuals who had a high rate of disc herniations (73%) were observed for an average of 5 years (range, 54-72 months). Four classes of variables (medical data including magnetic resonance imaging-identified disc abnormalities, general psychological factors, physical job characteristics, and psychosocial aspects of work) were assessed at baseline and follow-up. RESULTS: Disc herniations and neural compromise did not significantly worsen at follow-up, whereas disc degeneration progressed in 17 individuals (41.5%). Minor episodes of low back pain occurred in 19 individuals (41.3%), 6 of whom had to seek medical treatment and 5 of whom had to stop work temporarily. The requirement for low back pain-related medical consultation was predicted with high accuracy by listlessness, job satisfaction, and working in shifts (P < 0.001). Work incapacity was best predicted by physical job characteristics, job disaffection, and working in shifts (P < 0.01). CONCLUSION: Physical job characteristics and psychological aspects of work were more powerful than magnetic resonance imaging-identified disc abnormalities in predicting the need for low back pain-related medical consultation and the resultant work incapacity. However,the conclusions are still preliminary, and replication of the findings in larger and more representative study samples is needed.

Adult↗