Unusual Staining Pattern Research Articles

Monoclonal antibodies recognising cell surface molecules expressed by rat cerebellar interneurons

We describe monoclonal antibodies recognising three cell surface antigens expressed by rat cerebellar granule neurons. The antibodies were produced after immunising mice with a cerebellar glycoprotein preparation. 6-1-3 recognises a glycoprotein with an apparent molecular weight of 144000 daltons, and gives an unusual staining pattern on cultured neurons. 7-8D2 recognises postmitotic granule cells, but not their precursors in the external granular layer. The antigen was not detected in any brain region other than the cerebellum. 8-20-1 recognises a brain specific glycoprotein with an apparent molecular weight of 48 000 daltons, which appears on cerebellar granule cells only after the 10th postnatal day.

Unusual SCD in cancer cells: A phenomenon related to decreased BrdU incorporation?

The simultaneous presence of chromosome segments with and without sister chromatid differentiation (SCD) in the same metaphase was observed in a human melanoma cell line after BrdU incorporation for 48–72 hr. This phenomenon was related to the time of BrdU incorporation by the cells; i.e., it was not observed after exposure to BrdU for only 17–20 hr. It is proposed, therefore, that the unusual staining pattern is caused through reduced BrdU incorporation by the cells after completing the first division.

A rapid method for identification of constitutive heterochromatin of secondary constriction regions of human chromosomes 1, 9, and 16.

The secondary constriction regions (h) of chromosomes 1, 9, and 16 stained deep red by RBA (R-bands by BrdU using Giemsa)--a useful tool for demonstrating the constitutive heterochromatic heteromorphisms in these regions. The unusual staining pattern of bands p 12 to q11 of chromosome 3, which is late replicating, also is reported. The extended deep red region does not correspond to C-banding on chromosome 3. This technique does not require sequential banding by QFQ and CBG for detecting the h-region heteromorphisms.

Electron Microscopy of Fibroblasts from Myotonic Muscular Dystrophy Patients

Many genetic diseases can be demonstrated in skin cells cultured in vitro from patients with inborn errors of metabolism. Since myotonic muscular dystrophy (MMD) affects many organs other than muscle, it seems likely that this defect also might be expressed in fibroblasts. Detection of an alteration in cultured skin fibroblasts from patients would provide a valuable tool in the study of the disease as it would present a readily accessible and controllable system for examination. Furthermore, fibroblast expression would allow diagnosis of fetal and presumptomatic cases. An unusual staining pattern of MMD cultured skin fibroblasts as seen by light microscopy, namely, an increase in alcianophilia and metachromasia, has been reported; both these techniques suggest an altered glycosaminoglycan metabolism An altered growth pattern has also been described. One reference on cultured skin fibroblasts from a different dystrophy (Duchenne Muscular Dystrophy) reports increased cytoplasmic inclusions seen by electron microscopy. Also, ultrastructural alterations have been reported in muscle and thalamus biopsies from MMD patients, but no electron microscopical data is available on MMD cultured skin fibroblasts.