Mabel Cruz

Clinical, neurophysiological and immunological evidence of polyneuropathy in patients with monoclonal gammopathies

In this study we estimated the prevalence of polyneuropathy (PN) in patients with monoclonal gammopathies. 31 patients with monoclonal gammopathies (19 with monoclonal gammopathy of uncertain significance (MGUS), 10 with multiple myeloma (MM), and 2 with Waldenströms macroglobulinemia), were studied by clinical and neurophysiological examination, blood tests to exclude other causes of PN, ELISA assays to detect antibodies to peripheral nerve myelin (PNM), and antibodies to myelin associated glycoprotein (MAG). 11 of 31 patients (36%) had a clinical PN, 3 (10%) had a probable PN (signs but no symptoms), and 4 (13%) had a subclinical PN (only neurophysiological signs of PN). Thus, in total 18 patients (58%) had some form of PN, in contrast to an age-matched control group (n = 33) where only 2 persons (6%) had some form of PN; 1 had a probable PN and 1 had a subclinical PN. 3 patients had anti-PNM and anti-MAG antibodies of IgM isotype, all 3 patients showing a demyelinating PN. The remaining patients with PN had a mild or moderate distal PN. One patient had a myelopathy and 1 had amyotrophic lateral sclerosis (ALS). IgM isotype of the M-protein was associated with a high risk of clinical PN (5 out of 6 (83%)), in contrast to IgG (5 out of 18 (28%)) and IgA (1 out of 6 (17%)). We conclude that PN is a common finding in patients with monoclonal gammopathies, but only some of them are of the demyelinating type and associated with antibodies to PNM or MAG.

Multiple Sclerosis: Cells Secreting Antibodies Against Myelin-Associated Glycoprotein are Present in Cerebrospinal Fluid

We evaluated the B‐cell response in cerebrospinal fluid (CSF) and blood by enumerating cells secreting antibodies to myelin‐associated glycoprotein (MAG) and, for reference, to myelin basic protein (MBP), two myelin components which may constitute targets for autoimmune attack in multiple sclerosis (MS). Among 25 untreated MS patients, 12 had cells in CSF secreting anti‐MAG IgG antibodies (mean value 1 per 1429 CSF cells) and three also had cells secreting anti‐MAG antibodies of the IgM Isotype but at lower levels. In CSF from 2 out of 10 MS patients examined, anti‐MAG and anti‐MBP IgG antibody‐secreting cells were present concurrently. Antibody‐secreting cells were less frequent in blood and bone marrow, reflecting compartmentalization to CSF. Anti‐MAG antibody‐secreting cells were found in CSF from only I out of 27 control patients. The intrathecal production of anti‐MAG and anti‐MBP antibodies may be important in the pathogenesis of MS.

Surgery and Risk of Sporadic Creutzfeldt-Jakob Disease in Denmark and Sweden: Registry-Based Case-Control Studies

Background: Epidemiologic evidence of surgical transmission of sporadic Creutzfeldt-Jakob disease (sCJD) remains controversial. Methods: From Danish and Swedish registries we selected 167 definite and probable sCJD cases (with onset between 1987 and 2003) and 3,059 controls (835 age-, sex-, and residence-matched, and 2,224 unmatched). Independent of case/control status, surgical histories were obtained from National Hospital Discharge Registries. Surgical procedures were categorized by body system group and lag time to onset of sCJD. Exposure frequencies were compared using logistic regression. Results: A history of any major surgery, conducted ≧20 years before sCJD onset, was more common in cases than both matched (OR = 2.44, 95% CI = 1.46–4.07) and unmatched controls (OR = 2.25, 95% CI = 1.48–3.44). This observation was corroborated by a linear increase in risk per surgical discharge (OR = 1.57, 95% CI = 1.13–2.18; OR = 1.50, 95% CI = 1.18–1.91). Surgery of various body systems, including peripheral vessels, digestive system and spleen, and female genital organs, was significantly associated with increased sCJD risk. Conclusions: A variety of major surgical procedures constitute a risk factor for sCJD following an incubation period of many years. A considerable number of sCJD cases may originate from health care-related accidental transmission.

Nosocomial transmission of sporadic Creutzfeldt–Jakob disease: results from a risk-based assessment of surgical interventions

Objectives Evidence of surgical transmission of sporadic Creutzfeldt–Jakob disease (sCJD) remains debatable in part due to misclassification of exposure levels. In a registry-based case–control study, the authors applied a risk-based classification of surgical interventions to determine the association between a history of surgery and sCJD. Design Case–control study, allowing for detailed analysis according to time since exposure. Setting National populations of Denmark and Sweden. Participants From national registries of Denmark and Sweden, the authors included 167 definite and probable sCJD cases with onset during the period 1987–2003, 835 age-, sex- and residence-matched controls and 2224 unmatched. Surgical procedures were categorised by anatomical structure and presumed risk of transmission level. The authors used logistic regression to determine the odds ratio (OR) for sCJD by surgical interventions in specified time-windows before disease-onset. Results From comparisons with matched controls, procedures involving retina and optic nerve were associated with an increased risk at a latency of ≥1 year OR (95% CI) 5.53 (1.08 to 28.0). At latencies of 10 to 19 years, interventions on peripheral nerves 4.41 (1.17 to 16.6) and skeletal muscle 1.58 (1.01 to 2.48) were directly associated. Interventions on blood vessels 4.54 (1.01 to 20.0), peritoneum 2.38 (1.14 to 4.96) and skeletal muscle 2.04 (1.06 to 3.92), interventions conducted by vaginal approach 2.26 (1.14 to 4.47) and a pooled category of lower-risk procedures 2.81 (1.62 to 4.88) had an increased risk after ≥20 years. Similar results were found when comparing with unmatched controls. Interpretation This observation is in concordance with animal models of prion neuroinvasion and is likely to represent a causal relation of surgery with a non-negligible proportion of sCJD cases.

Inhibition of DNA synthesis in human gliomas by roscovitine

The early effect of 1-100 microM roscovitine, a purine analogue and cyclin-dependent kinase inhibitor, was studied on tissue specimens from eight human malignant gliomas. The tissue was incubated immediately after resection with DMEM containing [3H]methylthymidine plus vehicle alone or the proper concentration of roscovitine for 30-90 min. The DNA synthesis rate was assessed by measurement of [3H]methylthymidine incorporation into trichloroacetic acid insoluble material/mg protein/min. In all gliomas, 100 microM roscovitine inhibited DNA synthesis by 71-97% (average 89 +/- 8%, p<0.0001). This inhibitory effect of roscovitine appeared within 30 min of incubation and was concentration dependent.

Roscovitine inhibits ongoing DNA synthesis in human cervical cancer.

The effect of roscovitine, a purine analogue and cyclin dependent kinase inhibitor, on DNA synthesis rate in tissue mini-units obtained from human cervical cancers was investigated. Roscovitine (100 microM) gave a DNA synthesis rate inhibition by 61% (P<0.0001; range 23-93%) within 30 min of incubation. This inhibitory effect was concentration-dependent. The results suggest that the inhibition of tumor DNA synthesis rate is due to a direct effect on the DNA synthesis machinery via presently unknown mechanisms. In addition, the potential application of CDKs inhibitors as preventive agents is discussed.

Occurrence and isotype of antibodies against peripheral nerve myelin in serum from patients with peripheral neuropathy and healthy controls.

Antibodies against peripheral nerve myelin have previously been demonstrated in serum from patients with peripheral neuropathy and IgM paraproteinaemia, and a causal relationship has been suggested. Using enzyme-linked immunosorbent assay (ELISA), anti-myelin antibodies were found in sera from eight of 16 patients with polyneuropathy and paraproteinaemia, but also in 17% of 109 patients with peripheral neuropathy lacking monoclonal immunoglobulin, including five of 10 patients with Charcot-Marie-Tooth disease, and in 16% of 142 blood donors. The antibodies were mostly of IgM class in the two neuropathy groups, while blood donors had mostly IgA antibodies, and a few subjects of each group had antimyelin antibodies of two different isotypes. Western blot confirmed the ELISA results in a majority of antibody positive sera and revealed a 25-30 kD myelin target antigen for sera from the three groups, and for some of the non-paraproteinaemic sera also a 100 kD myelin target antigen. Our results demonstrate that the presence of serum autoantibodies against peripheral nerve myelin does not necessarily indicate a pathological event.

Susceptibility to demyelinating polyneuropathy in plasma cell dyscrasia may be influenced by amino acid position 9 of the HLA-DRβ chain

Fifty-five patients with plasma cell dyscrasias were investigated by genomic typing for HLA-DR and -DQ genes by restriction fragment length polymorphism, neurophysiology and for presence of anti-myelin-associated glycoprotein (MAG) antibodies. In 26 patients, a polyneuropathy (PN) of demyelinating type was established. Among these individuals, an association was found with the presence of a tryptophan amino acid residue at position 9 of the DR beta chain (P < 0.01). This position is part of the first hypervariable region of the DR beta chain, and may be of importance in determining preferential peptide-binding capacity of the HLA-DR molecule. The presence of anti-MAG antibodies in 15 out of 17 patients with an IgM M-component and demyelinating PN (14 of these 15 individuals carrying a tryptophan at position 9) supports the pathogenic role of an autoimmune response against MAG. The finding of an HLA class II association may indicate a pathogenic role of T cell immunity in this condition.

Lyme Arthritis: Oligoclonal Anti-Borrelia burgdorferi IgG Antibodies Occur in Joint Fluid and Serum

The antibody response to Borrelia (B.) burgdorferi, and to measles virus as control antigen, was analysed by agarose isoelectric focusing (AIF) and immunoblot of joint fluid and serum from 10 patients with Lyme arthritis and 10 controls with rheumatoid arthritis. Among the Lyme arthritis patients, six had oligoclonal anti‐B, burgdorferi IgG antibody bands in joint fluid and Corresponding serum, one patient had oligoclonal antibody bands in joint fluid only and also an elevated B. burgdorferi IgG in joint fluid to serum antibody ratio as evidence of intra‐joint production of specific antibodies, and the remaining three patients were negative for oligoclonal‐specific antibody bands. Absorption with B. burgdorferi imagen confirmed the specificity of the ofigoclonal antibody bands. They comigrated only partially on AIF with oligoclonal bands of total IgG and the specificity of most oligoclonal IgG in joint fluid and serum in Lyme arthritis remains undefined. Among the controls, no anti‐B, burgdorferi IgG antibodies were detected by AIF and immunoblot. Instead. 9 of the 10 rheumatoid arthritis patients had oligoclonal anti‐measles IgG antibody bands which were restricted to the joint fluid in three of them, indicating local production. We conclude that Lyme arthritis is often accompanied by an oligoclonal specific antibody response in joint fluid and serum simultaneously, and occasionally by intrasynovial synthesis of oligoclonal‐specific antibodies.

Fast and Sensitive Method for Simultaneous Measurement of Cell Proliferation Rate and Drug Sensitivity in Rat Cerebral Cortex

A proliferation assay based on the production of mini-units of tissue was adopted and modified for the simultaneous determination of cell proliferation rate and the effect of genistein in rat cerebral cortex. Mini-units of tissue were produced from rat cerebral cortex immediately after killing the animal and incubated with culture medium containing 3H-methyl-thymidine during 90 min. The proliferation rate was assessed by measurement of 3H-methyl-thymidine incorporation into trichloroacetic acid insoluble material/mg of protein/min. The mini-unit method preserves the neural-cell topological relation existing in vivo and, in addition, has several additional advantages: (1) the short incubation time required limits the metabolic changes, (2) the sensitivity to drugs can be assessed simultaneously with the cell proliferation rate, (3) the complete procedure can be performed within 4-6 h, and (4) many experiments can be performed with the tissue from one animal. Genistein in doses from 10 to 100 microM inhibited cell proliferation in a concentration-dependent manner. The percentage of inhibition was highest in young animals and decreased with increasing age. This method is a powerful tool for the study of drugs with short-time onset mechanisms of action and can be useful for the screening of new drugs.