Genome-wide association study of immunoglobulin light chain amyloidosis in three patient cohorts: comparison with myeloma

Immunoglobulin light chain (AL) amyloidosis is characterized by tissue deposition of amyloid fibers derived from immunoglobulin light chain. AL amyloidosis and multiple myeloma (MM) originate from monoclonal gammopathy of undetermined significance. We wanted to characterize germline susceptibility to AL amyloidosis using a genome-wide association study (GWAS) on 1229 AL amyloidosis patients from Germany, UK and Italy, and 7526 healthy local controls. For comparison with MM, recent GWAS data on 3790 cases were used. For AL amyloidosis, single nucleotide polymorphisms (SNPs) at 10 loci showed evidence of an association at P<10^-5 with homogeneity of results from the 3 sample sets; some of these were previously documented to influence MM risk, including the SNP at the IRF4 binding site. In AL amyloidosis, rs9344 at the splice site of cyclin D1, promoting translocation (11;14), reached the highest significance, P=7.80 × 10^-11; the SNP was only marginally significant in MM. SNP rs79419269 close to gene SMARCD3 involved in chromatin remodeling was also significant (P=5.2 × 10^-8). These data provide evidence for common genetic susceptibility to AL amyloidosis and MM. Cyclin D1 is a more prominent driver in AL amyloidosis than in MM, but the links to aggregation of light chains need to be demonstrated.

Assessment of low-flow CSF drainage as a treatment for AD: results of a randomized pilot study

OBJECTIVE

This prospective, randomized, controlled study was designed to investigate the safety, feasibility, and preliminary efficacy of long-term CSF drainage via a low-flow ventriculoperitoneal shunt in subjects suffering from AD.

METHODS

Twenty-nine subjects selected for probable AD (National Institute of Neurological and Communicative Diseases and Stroke-Alzheimer's Disease and Related Dementias Association criteria) were screened to exclude normal pressure hydrocephalus or other etiologies of dementia and randomized to treatment (shunt) or no treatment groups. The study endpoint was the comparison of group performance on psychometric testing at quarterly intervals for 1 year. Shunted subjects had CSF withdrawn for MAP-tau and Abeta((1-42)) assays at the same time intervals.

RESULTS

There was no mortality from the surgical procedure, and no patient sustained a subdural hematoma. Five notable postoperative adverse events, which resolved without permanent neurologic deficit, were reported in the shunt group. Group mean Mattis Dementia Rating Scale total scores showed little change over the year in the shunt-treatment group, in contrast to a decline in the control group (p = 0.06). Mini-Mental State Examination mean scores supported a trend in favor of shunt treatment (p = 0.1). There was a concomitant decrease in ventricular CSF concentrations of AD biomarkers MAP-tau and Abeta((1-42)).

CONCLUSIONS

The surgical procedure and the device are reasonably safe. Adverse events were consistent with shunt procedures for hydrocephalus in this older population. The endpoint data show a trend in favor of the treated group. A larger, randomized, double-blinded, controlled, clinical trial is underway.

The cerebrospinal fluid production rate is reduced in dementia of the Alzheimer's type

OBJECTIVE

To evaluate the production rate of CSF in patients with differing disease states.

METHODS

The authors measured the production rate of CSF in three groups of patients: five patients with PD below age 60 (aged 51 +/- 4 years, mean +/- SD), nine with PD over age 60 (aged 69 +/- 6 years, mean +/- SD), and seven with dementia of the Alzheimer's type (AD) (aged 72 +/- 9 years, mean +/- SD). This method, based on the Masserman technique, employs ventricular rather than a lumbar access to the CSF space. Furthermore, the volume of CSF removed during the procedure is only 3 mL rather than 10 mL.

RESULTS

These measurements indicate that the mean rate of CSF production in patients with PD under age 60 was 0.47 +/- 0.13 mL/minute, in patients with PD aged 60 or older the mean rate was 0.40 +/- 0.12 mL/minute, and in patients with AD the mean rate was 0.20 +/- 0.06 mL/minute.

CONCLUSION

These results indicate that the rate of CSF production in patients with PD is normal, and that the rate of CSF production in patients with AD is markedly reduced.

Volume MRI and MRSI techniques for the quantitation of treatment response in brain tumors: presentation of a detailed case study

Patients with primary brain tumors may be considered for several different treatments during the course of their disease. Assessments of disease progression and response to therapy are typically performed by visual interpretation of serial MRI examinations. Although such examinations provide useful morphologic information, they are unable to reliably distinguish active tumor from radiation necrosis. This poses a particular problem in the assessment of response to localized radiation therapies such as gamma knife radiosurgery. In this paper, we present methodology for evaluating changes in tissue morphology and metabolism based on serial volumetric MRI and magnetic resonance spectroscopic imaging (MRSI) examinations. Registration and quantitative analysis of these data provide measurements of the temporal and spatial distributions of gadolinium enhancement and of N-acetylasparate, choline, creatine, and lactate/lipid. The key features of this approach and the potential clinical benefits are illustrated by a detailed analysis of six serial MRI/MRSI examinations and three serial 1-[F-18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) studies on a patient with a recurrent anaplastic astrocytoma.

Alignment of volume MR images and high resolution [18F]fluorodeoxyglucose PET images for the evaluation of patients with brain tumors

PURPOSE

The goal of the study was to investigate the use of automated registration techniques for interpretation of volume MR and high resolution FDG-PET images that were obtained from patients with brain tumors.

METHOD

Twenty-one patients with brain tumors were studied on one or more occasions using MRI and high resolution FDG-PET. The data were aligned using automated volume- and surface-matching algorithms. Composite images comprising the resliced pre- and postgadolinium spoiled GRE, T2-weighted SE, and PET data were constructed to correlate intensities of regions on the PET images with regions that corresponded to normal gray matter, white matter, and gadolinium enhancement.

RESULTS

The accuracy of registration between the MR and PET images was estimated to be within 1-2 mm based upon the distance between surfaces of the outside of the head. In 12 of the 24 examinations, there were diagnoses of recurrent tumor, with only 5 of these exhibiting regions of higher FDG uptake than normal gray matter. For 19 of the 24 studies, the anatomic context provided by the registered MR images was found to be important in distinguishing recurrent tumor from necrosis based upon FDG uptake.

CONCLUSION

The automated alignment was found to be an important factor in interpreting the high resolution PET images. This was particularly true for small lesions close to the cortex and for situations where FDG uptake had been reduced by prior treatment with radiation therapy.

Operative management of bilateral facet dislocation

Fifty-two patients with acute traumatic bilateral locked facets were treated at one trauma center during a 3 1/2-year period (July, 1987, to December, 1990). The patients presented with complete motor quadriplegia (34 cases), incomplete myelopathy (13 cases), or intact long-tract function (five cases). The injuries occurred at C2-3 (one patient, with intact function), C4-5 (12 patients), C5-6 (16 patients), C6-7 (19 patients), and C7-T1 (four patients). Immediate traction (with increasing weight and serial x-ray studies) and/or induction of general anesthesia and muscle relaxation reduced the dislocation in 40 patients, but 12 needed prompt operative reduction as their injuries failed to reduce within 4 hours. Stabilization was indicated for all patients, but three did not undergo surgery: two elderly patients with complete injuries (one refused surgery and one died), and one patient with multiple injuries (fusion was achieved by halo-vest immobilization for 3 months). Of the 49 patients treated operatively, 23 (44.2%) underwent surgery on the day of injury and 26 on a delayed basis (mean 8.7 days postinjury). Surgical treatment included fusion of the posterior facet to a spinous process (44 cases), an anterior Caspar plate technique (three cases), and both procedures (two cases). Of these 49 patients, three (6.1%) with complete injuries died due to an adult respiratory distress syndrome. Improvement of cord function, judged by functional grade change, was observed at discharge in 15 patients (31.9%) and in 15 (71.4%) of the 21 patients with a 1-year follow-up period. Of the 34 patients with complete myelopathy on admission, three are ambulatory after 1 year, and 13 others have gained function in at least one nerve root. It is concluded that prompt reduction (nonoperative or surgical) and internal stabilization facilitate recovery even in neurologically compromised patients, and that early operative intervention is a wiser option than conservative management. This report also documents a higher incidence of this injury without deficit (five of the 52 cases) than reported in other series.

A highly sensitive immunoenzymometric assay involving "common-capture" particles and membrane filtration

This highly sensitive immunoenzymometric method involves monoclonal antibodies, a common-capture microsphere, and a rapid, membrane-filtration separation step. The common-capture solid phase is monoclonal anti-fluorescein antibody convalently attached to 6.5 micron-diameter latex particles. In sandwich-type assays for large-molecule analytes, the capture antibody is conjugated with fluorescein isothiocyanate and the probe antibody is conjugated with beta-galactosidase (EC 3.2.1.23). In competitive assays for small analytes, the analyte-beta-galactosidase conjugate competes with the analyte in the clinical samples for the fluoresceinated capture antibody. After simultaneous incubation of the reagents for 2 h, the bound and unbound reagents are separated by filtration through the bottom of each well of a 96-well plate. Substrate (4-methylumbelliferyl-beta-D-galactopyranoside) is then added to the wells, and the rate of product formation is determined kinetically for 12 min. The rate is proportional to the concentration of analyte in the sandwich assays and inversely proportional in the competitive assays. The assay results for choriogonadotropin, thyrotropin, digoxin, and thyroxin show the assay to be sensitive, rapid, and applicable to any size analyte. With this system, several different sandwich and (or) competitive-type assays can be performed simultaneously on the same plate.

A highly sensitive immunoenzymometric assay involving "common-capture" particles and membrane filtration

This highly sensitive immunoenzymometric method involves monoclonal antibodies, a common-capture microsphere, and a rapid, membrane-filtration separation step. The common-capture solid phase is monoclonal anti-fluorescein antibody convalently attached to 6.5 micron-diameter latex particles. In sandwich-type assays for large-molecule analytes, the capture antibody is conjugated with fluorescein isothiocyanate and the probe antibody is conjugated with beta-galactosidase (EC 3.2.1.23). In competitive assays for small analytes, the analyte-beta-galactosidase conjugate competes with the analyte in the clinical samples for the fluoresceinated capture antibody. After simultaneous incubation of the reagents for 2 h, the bound and unbound reagents are separated by filtration through the bottom of each well of a 96-well plate. Substrate (4-methylumbelliferyl-beta-D-galactopyranoside) is then added to the wells, and the rate of product formation is determined kinetically for 12 min. The rate is proportional to the concentration of analyte in the sandwich assays and inversely proportional in the competitive assays. The assay results for choriogonadotropin, thyrotropin, digoxin, and thyroxin show the assay to be sensitive, rapid, and applicable to any size analyte. With this system, several different sandwich and (or) competitive-type assays can be performed simultaneously on the same plate.