| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Technical Advances |
From the Laboratory of Pathology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland
| Abstract |
|---|
|
|
|---|
| Introduction |
|---|
|
|
|---|
Microdissection from stained tissue sections and related techniques allow the isolation of morphologically identified cell populations down to the single-cell level for genetic analysis and thus can circumvent or ameliorate the problem of tissue heterogeneity.1-8 Microdissected tissue as a source of genomic DNA was used successfully for the detection of heterozygosity in primary tumors, detection of tumor-specific genetic alterations in preneoplastic changes adjacent to invasive tumors,9-13 and the assignment of the malignant cells of Hodgkin's disease to the B cell lineage.14,15 More recently, tissue fragments obtained by microdissection of routinely stained frozen sections have also been used for the isolation of mRNA amenable to reverse transcription polymerase chain reaction (RT-PCR), the generation of expression libraries, and related techniques.8,16-20
However, routinely stained frozen sections without coverslip as necessary for microdissection show greatly reduced cellular detail, which diminishes the ability to distinguish and isolate specific cell populations from complex lesions with an intimate mixture of morphologically similar cell types, such as lymphomas or carcinomas with a diffuse growth pattern. Immunohistochemical staining of frozen sections could help to identify and isolate specific cell populations, even of identical morphology, according to their antigen expression, allowing a more precise microdissection. However, standard immunohistochemical staining protocols usually require several hours of incubation in aqueous media, resulting in significant degradation and loss of RNA through activation of tissue RNAses and other factors.
We therefore established a rapid immunostaining technique for frozen sections, which, in combination with laser capture microdissection (LCM),3,21 allows very fast, technically easy and precise isolation of specific cell populations for mRNA analysis.
| Materials and Methods |
|---|
|
|
|---|
Snap-frozen tissue blocks of normal and neoplastic lymph node, breast, and prostate were chosen from the tissue bank of the Laboratory of Pathology, National Cancer Institute. Four- to eight-micron serial frozen sections were cut on a standard cryostat with a clean blade, and two sections each were mounted on Superfrost Plus (Fisher Scientific, Pittsburgh, PA) or poly-L-lysine-precoated (C to C Laboratory Supplies, Chicago, IL) glass slides. The unfixed sections were immediately stored at -80°C.
The frozen sections were thawed at room temperature for 30 to 60
seconds without drying and immersed immediately in one of the following
fixatives: cold acetone (5 minutes), methanol (5 minutes), 4%
paraformaldehyde (5 minutes), 70% ethanol (15 to 30 seconds),
ethanol/formalin (3:1, 1 minute), and ethanol 70% (15 seconds)
followed by acetone (5 minutes). After fixation, the slides were rinsed
briefly in 1X phosphate-buffered saline (PBS), pH 7.4, and subjected to
immunostaining. The immunohistochemical staining was performed with the
DAKO Quick Staining kit (DAKO Corp., Carpinteria, CA), a three-step
streptavidin-biotin technique with prediluted mono- or polyclonal
(rabbit) primary antibodies optimized for very short staining times.
The slides were incubated at room temperature with the primary and
secondary antibodies and the tertiary reagent for 90 to 120 seconds
each and briefly rinsed with 1X PBS between each step. After color
development with diaminobenzidine (DAB) for 3 to 5 minutes and
counterstaining with hematoxylin for 15 to 30 seconds, the sections
were dehydrated in graded alcohols (15 seconds each) and xylene (twice
for 2 minutes each) and air dried. The primary antibodies used are
listed in Table 1
. For primary antibodies
other than the prediluted DAKO Quick Staining kit antibodies, the
dilutions were determined individually (Table 1)
, and the incubation
time was prolonged to 5 to 10 minutes. Placental RNAse inhibitor
(Perkin Elmer, Branchburg, NJ) was added to the primary antibody and
the DAB solution in a concentration of 200 to 400 U/ml. Negative
controls included omission of the primary antibody and incubation with
an irrelevant antiserum. One ethanol-fixed section of each run was
stained with Mayer's hematoxylin (30 seconds) and eosin (10 seconds)
and dehydrated as described above. All solutions were prepared with
DEPC-treated water.
|
After immunostaining and microscopic control of staining quality and tissue preservation, one of the two sections on the slide was scraped off with a clean razor blade for RNA extraction as described below. The remaining section was used for microdissection using a PixCell laser capture microscope with an infrared diode laser (Arcturus Engineering, Santa Clara, CA) as described previously with modifications.3,21 In brief, the dehydrated tissue section is overlaid with a thermoplastic membrane mounted on optically transparent caps, and cells are captured by focal melting of the membrane through laser activation. After visual control of the completeness of dissection, the captured tissue was immersed in denaturation solution. Caps briefly placed onto the section without laser activation were used as negative controls.
RNA Extraction, DNAse Treatment and Reverse Transcription
RNA was obtained from both microdissected as well as scraped tissue sections with the Micro RNA isolation kit (Stratagene, La Jolla, CA) as described previously.3,22 The RNA pellet was redissolved in water treated with sterile diethylpyrocarbonate and incubated with 20 U of DNAse I (GenHunter Corp., Nashville, TN) for 2 hours at 37°C. After re-extraction of RNA, reverse transcription was performed using 12 µl of RNA, 2.5 µmol/L random hexamers, 25 µmol/L dNTPs, and 100 U of MMLV reverse transcriptase (GenHunter). For each sample, a mock reaction without addition of reverse transcriptase was performed.
cDNA Amplification
The primers, their sources, and the expected sizes of the cDNA
amplification products are listed in Table 2
. A total of 35 to 40 cycles of
amplification were performed using either conventional PCR or hot-start
PCR employing AmpliTaq Gold LD (Perkin Elmer) in
conjunction with the TaqStart antibody (Clontech, Palo Alto,
CA). Appropriate negative controls including amplification of the mock
RT reaction product were performed in each run. The PCR products were
separated on a 2% agarose gel stained with ethidium bromide.
|
| Results |
|---|
|
|
|---|
|
LCM was performed successfully with all tested tissue types, and the
efficiency and specificity of the capture of selected areas was
virtually independent from the fixatives, antibodies, or staining
procedures used (Figure 1)
. The use of charged or
poly-L-lysine-coated slides did not interfere with LCM, and
nonspecific capture and transfer due to detachment of tissue
surrounding the area adherent to the membrane was virtually absent.
However, any drying of the sections before fixation prevented LCM
almost completely, probably due to increased tissue adhesion to the
pretreated slides.
The factors influencing recovery and quality of mRNA are listed in
Table 3
. Acetone, methanol, or
ethanol/acetone fixation allowed amplification of actin cDNA fragments
by RT-PCR from as little as 10 shots (Figure 2)
, corresponding to approximately 200
cells, whereas ethanol and paraformaldehyde fixation rendered
significantly less or no amplifiable cDNA (Figure 3)
. Shorter products were amplified more
efficiently than longer products, but ß-actin fragments of 650 bp
were successfully amplified from larger amounts of microdissected
tissue. No signals were observed after amplification of the negative RT
control without addition of reverse transcriptase. However, reduction
of the DNAse I treatment frequently led to the appearance of products
of similar length with the actin primer set in the negative RT control,
probably due to processed pseudogenes present in contaminating genomic
DNA. In addition to these housekeeping genes, cell-specific transcripts
such as CD4 and CD19 were successfully amplified from microdissected,
immunostained slides from less than 1000 captured cells. Selective
dissection of B cells (Figure 1D)
, T cells, or nonlymphoid cells from
immunostained sections yielded significantly enriched populations,
resulting in predominant amplification of the mRNA specific for the
targeted cell type (Figure 4)
.
|
|
|
|
| Discussion |
|---|
|
|
|---|
The feasibility of mRNA extraction from microdissected, routinely stained, or unstained frozen sections for various applications has been demonstrated by several groups, using a variety of microdissection techniques and RNA isolation protocols.3,8,16-20 Good RNA quality was obtained with short staining times for routine histological stains, such as H&E, in conjunction with precipitating fixatives, such as ethanol or acetone, and conventional protection against RNAses. Although PCR analysis of genomic DNA has been performed successfully from microdissected, immunostained frozen as well as paraffin sections,15,23 the long periods of tissue immersion in aqueous media required for conventional immunohistochemistry is deleterious for RNA, mainly through activation of endogenous RNAses.
Therefore, the adaptation of immunohistochemistry for immuno-LCM requires a significant departure from conventional immunostaining protocols. With our method, excellent staining results were obtained despite the significant reduction in staining time and other modifications to avoid degradation by RNAses. Although some primary antibodies requiring longer incubation times may not be suitable for immuno-LCM, our limited testing showed that the majority of primary antibodies will give good immunostaining if their concentration is adjusted accordingly. The fixatives used, the staining time, and the addition of RNAse inhibitor24 were the most crucial factors determining RNA quality. Precipitating agents, especially acetone and methanol, proved superior to cross-linking reagents such as paraformaldehyde, which led to a significant decline in amplifiable RNA. Currently, efforts are under way in our laboratory to use low-temperature paraffin embedding in conjunction with the fixatives mentioned above to combine the superior morphology of paraffin-embedded tissue with good preservation of RNA.
For the successful performance of LCM after immunostaining, careful control of tissue adhesion to the slide is necessary to avoid detachment of sections during the staining procedure without compromising laser capture. Although pretreated glass slides were well suited for immuno-LCM, even short drying periods before fixation or storage of stained slides for several days greatly diminished tissue capture. Another critical factor is complete dehydration of the sections after immunostaining. Rapid processing of stained slides allowed complete and specific transfer of selected cells over a wide range of laser pulse energy and spot size and in a variety of tested tissues.
With the commercially available laser capture microscope used in our study, the smallest routinely attainable spot sizes were between 10 and 20 µm. A new prototype currently under development allows spot sizes of less than 5 µm, equivalent to single-cell microdissection.21 Although the intimate intermingling of different cell types in many tissues sets limits to the specificity of LCM, especially concerning cytoplasmic RNA, the easy identification of immunostained cells allows a faster and more precise sampling procedure with sufficient enrichment of the desired cell type. The successful amplification of cell-specific transcripts with fragment sizes of more than 400 bp from less than 1000 cells without employment of more sensitive techniques, such as nested PCR, demonstrates that immuno-LCM-derived RNA can likely be used for applications such as cDNA library construction or hybridization to cDNA microarrays.16,25 In comparison with micromanipulator-based techniques, immuno-LCM is orders of magnitude faster and allows procurement of a large number of cells in a short period of time, which increases the yield of high quality RNA and dilutes out contaminating cells. This might help to reduce artifacts introduced by the use of very small numbers of cells, such as loss of RNA through cell sectioning, contamination, or biased template amplification through a high number of cycles.
Depending on the type of RNA analysis desired, our procedure for RNA extraction might be exchanged for simpler protocols.17,20,24,26 However, we consider the DNAse I treatment an indispensable step for obtaining DNA-free RNA. In our experience, any reduction in the time of digestion or in the concentration of the enzyme to levels recommended in the literature frequently revealed the presence of contaminating DNA in the mock RT control, underlining the necessity for stringent methods of RNA purification.
In conclusion, we demonstrate that immuno-LCM allows recovery of high quality mRNA from immunophenotypically defined cell populations in complex primary tissues. The technique is fast, easy to perform, and versatile. mRNA obtained by immuno-LCM may be used for the generation of expression libraries or the screening of cDNA arrays, thus allowing in vivo analysis of tissue-, cell-, and function-specific gene expression patterns.
| Acknowledgements |
|---|
| Footnotes |
|---|
Supported in part by a grant from the Austrian Science Funds to F. Fend (Erwin-Schroedinger Stipendium J1402 MED).
Accepted for publication September 25, 1998.
| References |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
A. P. Lenz, K. S. Williamson, B. Pitts, P. S. Stewart, and M. J. Franklin Localized Gene Expression in Pseudomonas aeruginosa Biofilms Appl. Envir. Microbiol., July 15, 2008; 74(14): 4463 - 4471. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. L. Williams, M. W. Schwartz, L. S. Bastian, J. E. Blevins, and D. G. Baskin Immunocytochemistry and Laser Capture Microdissection for Real-time Quantitative PCR Identify Hindbrain Neurons Activated by Interaction Between Leptin and Cholecystokinin J. Histochem. Cytochem., March 1, 2008; 56(3): 285 - 293. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. Saturno, M. Pesenti, C. Cavazzoli, A. Rossi, A. M. Giusti, B. Gierke, M. Pawlak, and M. Venturi Expression of Serine/Threonine Protein-Kinases and Related Factors in Normal Monkey and Human Retinas: The Mechanistic Understanding of a CDK2 Inhibitor Induced Retinal Toxicity Toxicol Pathol, December 1, 2007; 35(7): 972 - 983. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Yakirevich, C. L. Jackson, P. A. Meitner, D. MacKenzie, R. Tavares, L. Robinson-Bostom, R. A. DeLellis, and M. B. Resnick Analysis of T-Cell Clonality Using Laser Capture Microdissection and High-Resolution Microcapillary Electrophoresis J. Mol. Diagn., September 1, 2007; 9(4): 490 - 497. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. J. Buckanovich, D. Sasaroli, A. O'Brien-Jenkins, J. Botbyl, R. Hammond, D. Katsaros, R. Sandaltzopoulos, L. A. Liotta, P. A. Gimotty, and G. Coukos Tumor Vascular Proteins As Biomarkers in Ovarian Cancer J. Clin. Oncol., March 1, 2007; 25(7): 852 - 861. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. von Smolinski, M. Blessenohl, C. Neubauer, K. Kalies, and A. Gebert Validation of a Novel Ultra-Short Immunolabeling Method for High-Quality mRNA Preservation in Laser Microdissection and Real-Time Reverse Transcriptase-Polymerase Chain Reaction J. Mol. Diagn., May 1, 2006; 8(2): 246 - 253. [Abstract] [Full Text] [PDF] |
||||
![]() |
W.-S. Chu, Q. Liang, Y. Tang, R. King, K. Wong, M. Gong, M. Wei, J. Liu, S.-H. Feng, S.-C. Lo, et al. Ultrasound-accelerated Tissue Fixation/Processing Achieves Superior Morphology and Macromolecule Integrity with Storage Stability J. Histochem. Cytochem., May 1, 2006; 54(5): 503 - 513. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Korn, S. Rohrig, S. Schulze-Kremer, and U. Brinkmann Common denominator procedure: a novel approach to gene-expression data mining for identification of phenotype-specific genes Bioinformatics, June 1, 2005; 21(11): 2766 - 2772. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Fuke, T. Betsuyaku, Y. Nasuhara, T. Morikawa, H. Katoh, and M. Nishimura Chemokines in Bronchiolar Epithelium in the Development of Chronic Obstructive Pulmonary Disease Am. J. Respir. Cell Mol. Biol., October 1, 2004; 31(4): 405 - 412. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Quan, T. He, S. Kang, J. J. Voorhees, and G. J. Fisher Solar Ultraviolet Irradiation Reduces Collagen in Photoaged Human Skin by Blocking Transforming Growth Factor-{beta} Type II Receptor/Smad Signaling Am. J. Pathol., September 1, 2004; 165(3): 741 - 751. [Abstract] [Full Text] [PDF] |
||||
![]() |
S. Suzuki, M. Asamoto, K. Tsujimura, and T. Shirai Specific differences in gene expression profile revealed by cDNA microarray analysis of glutathione S-transferase placental form (GST-P) immunohistochemically positive rat liver foci and surrounding tissue Carcinogenesis, March 1, 2004; 25(3): 439 - 443. [Abstract] [Full Text] [PDF] |
||||
![]() |
M C R F van Dijk, P D M Rombout, H B P M Dijkman, D J Ruiter, and M R Bernsen Improved resolution by mounting of tissue sections for laser microdissection Mol. Pathol., August 1, 2003; 56(4): 240 - 243. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. P. Diggle, S. Cruickshank, J. D. Olsburgh, S. Pellegrin, B. Smith, R. E. Banks, P. J. Selby, M. A. Knowles, J. Southgate, and P. Harnden Identification of Genes Up-Regulated in Urothelial Tumors: The 67-kd Laminin Receptor and Tumor-Associated Trypsin Inhibitor Am. J. Pathol., August 1, 2003; 163(2): 493 - 504. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Zhang, N. Yang, J.-W. Park, D. Katsaros, S. Fracchioli, G. Cao, A. O'Brien-Jenkins, T. C. Randall, S. C. Rubin, and G. Coukos Tumor-derived Vascular Endothelial Growth Factor Up-Regulates Angiopoietin-2 in Host Endothelium and Destabilizes Host Vasculature, Supporting Angiogenesis in Ovarian Cancer Cancer Res., June 15, 2003; 63(12): 3403 - 3412. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Zhang, N. Yang, J.-R. Conejo-Garcia, D. Katsaros, A. Mohamed-Hadley, S. Fracchioli, K. Schlienger, A. Toll, B. Levine, S. C. Rubin, et al. Expression of Endocrine Gland-derived Vascular Endothelial Growth Factor in Ovarian Carcinoma Clin. Cancer Res., January 1, 2003; 9(1): 264 - 272. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Nishioka, T. Kohno, M. Tani, N. Yanaihara, Y. Tomizawa, A. Otsuka, S. Sasaki, K. Kobayashi, T. Niki, A. Maeshima, et al. MYO18B, a candidate tumor suppressor gene at chromosome 22q12.1, deleted, mutated, and methylated in human lung cancer PNAS, September 17, 2002; 99(19): 12269 - 12274. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Uneyama, M. Shibutani, N. Masutomi, H. Takagi, and M. Hirose Methacarn Fixation for Genomic DNA Analysis in Microdissected, Paraffin-embedded Tissue Specimens J. Histochem. Cytochem., September 1, 2002; 50(9): 1237 - 1245. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. A. Craven, N. Totty, P. Harnden, P. J. Selby, and R. E. Banks Laser Capture Microdissection and Two-Dimensional Polyacrylamide Gel Electrophoresis : Evaluation of Tissue Preparation and Sample Limitations Am. J. Pathol., March 1, 2002; 160(3): 815 - 822. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Betsuyaku, G. L. Griffin, M. A. Watson, and R. M. Senior Laser Capture Microdissection and Real-Time Reverse Transcriptase/ Polymerase Chain Reaction of Bronchiolar Epithelium after Bleomycin Am. J. Respir. Cell Mol. Biol., September 1, 2001; 25(3): 278 - 284. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. M. Gjerdrum, I. Lielpetere, L. M. Rasmussen, K. Bendix, and S. Hamilton-Dutoit Laser-Assisted Microdissection of Membrane-Mounted Paraffin Sections for Polymerase Chain Reaction Analysis: Identification of Cell Populations Using Immunohistochemistry and in Situ Hybridization J. Mol. Diagn., August 1, 2001; 3(3): 105 - 110. [Abstract] [Full Text] [PDF] |
||||
![]() |
L C Lawrie, S Curran, H L McLeod, J E Fothergill, and G I Murray Application of laser capture microdissection and proteomics in colon cancer Mol. Pathol., August 1, 2001; 54(4): 253 - 258. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Jin, I. Tsumanuma, K. H. Ruebel, J. M. Bayliss, and R. V. Lloyd Analysis of Homogeneous Populations of Anterior Pituitary Folliculostellate Cells by Laser Capture Microdissection and Reverse Transcription-Polymerase Chain Reaction Endocrinology, May 1, 2001; 142(5): 1703 - 1709. [Abstract] [Full Text] |
||||
![]() |
K. S. Simpson, M. J. Byers, and T. E. Curry Jr. Spatiotemporal Messenger Ribonucleic Acid Expression of Ovarian Tissue Inhibitors of Metalloproteinases throughout the Rat Estrous Cycle Endocrinology, May 1, 2001; 142(5): 2058 - 2069. [Abstract] [Full Text] |
||||
![]() |
L. Fink, T. Kinfe, W. Seeger, L. Ermert, W. Kummer, and R. M. Bohle Immunostaining for Cell Picking and Real-Time mRNA Quantitation Am. J. Pathol., November 1, 2000; 157(5): 1459 - 1466. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. H. Wong, J. R. Saam, T. S. Stappenbeck, C. H. Rexer, and J. I. Gordon Genetic mosaic analysis based on Cre recombinase and navigated laser capture microdissection PNAS, October 23, 2000; (2000) 230237997. [Abstract] [Full Text] |
||||
![]() |
F. Fend and M. Raffeld Laser capture microdissection in pathology J. Clin. Pathol., September 1, 2000; 53(9): 666 - 672. [Abstract] [Full Text] [PDF] |
||||
![]() |
G. J. Gordon, W. B. Coleman, and J. W. Grisham Temporal Analysis of Hepatocyte Differentiation by Small Hepatocyte-Like Progenitor Cells during Liver Regeneration in Retrorsine-Exposed Rats Am. J. Pathol., September 1, 2000; 157(3): 771 - 786. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. R. Emmert-Buck, R. L. Strausberg, D. B. Krizman, M. F. Bonaldo, R. F. Bonner, D. G. Bostwick, M. R. Brown, K. H. Buetow, R. F. Chuaqui, K. A. Cole, et al. Molecular Profiling of Clinical Tissue Specimens: Feasibility and Applications J. Mol. Diagn., May 1, 2000; 2(2): 60 - 66. [Full Text] |
||||
![]() |
S Curran, J A McKay, H L McLeod, and G I Murray Laser capture microscopy Mol. Pathol., April 1, 2000; 53(2): 64 - 68. [Abstract] [Full Text] |
||||
![]() |
T Kasai, S Shimajiri, and H Hashimoto Detection of SYT-SSX fusion transcripts in both epithelial and spindle cell areas of biphasic synovial sarcoma using laser capture microdissection Mol. Pathol., April 1, 2000; 53(2): 107 - 110. [Abstract] [Full Text] |
||||
![]() |
M. R. Emmert-Buck, R. L. Strausberg, D. B. Krizman, M. F. Bonaldo, R. F. Bonner, D. G. Bostwick, M. R. Brown, K. H. Buetow, R. F. Chuaqui, K. A. Cole, et al. Molecular Profiling of Clinical Tissue Specimens : Feasibility and Applications Am. J. Pathol., April 1, 2000; 156(4): 1109 - 1115. [Full Text] [PDF] |
||||
![]() |
J. Serth, M. A. Kuczyk, U. Paeslack, R. Lichtinghagen, and U. Jonas Quantitation of DNA Extracted after Micropreparation of Cells from Frozen and Formalin-Fixed Tissue Sections Am. J. Pathol., April 1, 2000; 156(4): 1189 - 1196. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. R. Englert, G. V. Baibakov, and M. R. Emmert-Buck Layered Expression Scanning: Rapid Molecular Profiling of Tumor Samples Cancer Res., March 1, 2000; 60(6): 1526 - 1530. [Abstract] [Full Text] |
||||
![]() |
N. L. Simone, A. T. Remaley, L. Charboneau, E. F. Petricoin III, J. W. Glickman, M. R. Emmert-Buck, T. A. Fleisher, and L. A. Liotta Sensitive Immunoassay of Tissue Cell Proteins Procured by Laser Capture Microdissection Am. J. Pathol., February 1, 2000; 156(2): 445 - 452. [Abstract] [Full Text] [PDF] |
||||
![]() |
F. Fend, L. Quintanilla-Martinez, S. Kumar, M. W. Beaty, L. Blum, L. Sorbara, E. S. Jaffe, and M. Raffeld Composite Low Grade B-Ce |