Immunocytochemistry on paraffin wax Golgi-Cox impregnated central nervous tissue.

We present a new application of an immunocytochemical technique on central nervous tissue which utilizes Golgi-Cox impregnated paraffin embedded material. Sections of normal and pathological brain and spinal cord, from both Golgi-Cox impregnated tissue and for comparison formol saline fixed tissue, were studied with the following antibodies: glial fibrillary acidic protein, myelin basic protein, neurofilament, neurone specific enolase, protein gene product 9.5, ubiquitin and vimentin. Optimal results were obtained with most of the antibodies after adapting the technique by using different pretreatments including enzymes and de-impregnation methods. In addition to the Golgi-Cox impregnated structures, neuronal, glial and mesenchymal antigens were well demonstrated and the relationships between these structures clearly visible. The antigenic retention of the tissue after Golgi-Cox impregnation allowed successful immunostaining to be performed either alone or as a combined procedure. It is therefore possible to study a variety of antigens and neuronal processes in the same section with maximum results. Immunocytochemical methodology in combination with this fixative opens a new avenue for the immunocytochemical and cytomorphological study of central nervous tissue with the added advantage of making the best use of the versatility and durability of paraffin embedded material.

Changes in the myelinated axons of femoral nerve in amyotrophic lateral sclerosis.

Myelinated fibres in femoral nerves removed from amyotrophic lateral sclerosis (ALS) cases at post mortem were compared with age matched controls. A technique for processing whole transverse sections of the nerves for osmication and subsequent morphometric analysis is described. Although areas depleted in myelinated fibres were seen in the nerves from the ALS group, no statistically significant difference was shown due to wide variations in the controls. However, the ALS nerves showed a degree of disruption in the myelin which was not apparent in the controls. The most obvious effect was widespread "wrinkling" of the myelin in both large and small fibres from the ALS nerves. This phenomenon is the initial stage of a process which eventually results in uneven myelin thickness and nodal swellings and finally myelin ovoids and balls. We illustrate the steps in the progression of this degeneration with teased nerve studies and electron microscopy and propose that there are qualitative changes in the myelin of peripheral nerve in ALS. It seems likely that these are secondary effects resulting from axonal degeneration caused by deterioration and loss of anterior horn cells in the spinal cord.

Oligodendrogliomas: a clinical, histological, immunocytochemical and lectin-binding study.

We have studied 27 oligodendrogliomas with a panel of antibodies (vimentin, GFAP, S-100 protein, myelin basic protein, CAM 5.2) and of lectins (WGA, Con A, PNA, RCA, DBA, SBA) to different glycoproteins. There were 16 well-differentiated tumours, including one gliofibrillary and 11 anaplastic oligodendrogliomas, three of which were gliofibrillary. Four cases showed positivity for vimentin, three of which were anaplastic tumours. Fifteen cases were positive for S-100 protein (nine well-differentiated and six anaplastic tumours) and 13 contained GFAP-positive cells (three well-differentiated and 10 anaplastic tumours). WGA binding was positive in 75% of well-differentiated and 63% of anaplastic oligodendrogliomas, the corresponding figures were 50% and 45% for PNA, 37% and 81% for Con-A and 25% and 54% for RCA. On the basis of the results with lectin binding, we believe that there are changes in the spectrum of tumour cell-associated lectin-like proteins during malignant transformation. Our observations also suggest that the pattern of lectin expression can undergo substantial changes in the course of differentiation.

The monocyte/macrophage infiltrate in 35 medulloblastomas: a paraffin-wax study.

We have studied formalin fixed, paraffin-wax embedded tissue from 35 medulloblastomas, collected over 23 years (27 non-desmoplastic and 8 desmoplastic) with KP1 and Mac387 two monoclonal anti-monocytes/macrophage (M/Ms) antibodies recommended for use on paraffin wax embedded tissue. In non-desmoplastic medulloblastomas, outside areas of necrosis, M/Ms were detected in 50% of cases with KP1 and 52% with Mac387. M/Ms were seen in 100% of desmoplastic medulloblastomas with both antibodies. Semiquantitative assessment revealed that, on average, desmoplastic tumors had at least three times as many infiltrating M/Ms as non-desmoplastic tumors. There was no significant difference in the findings with the two antibodies or, between recently embedded and "older" tumors. The findings may be indicative of the presence of a host M/Ms immune response in medulloblastoma, which may be more accentuated in desmoplastic medulloblastomas. Furthermore, we conclude that these antibodies are quite suitable for the study of infiltrating M/Ms, thus lessening (but not obviating) the need for frozen tissue for immunohistological studies.