Optimization of tyrosine hydroxylase immunocytochemistry in paraffin sections using pretreatment with proteolytic enzymes

Immunocytochemical localization of tyrosine hydroxylase (TH) was performed on paraffin sections pretreated with various proteolytic enzymes. It was found that pretreatment with trypsin (1.2 mg/ml) for 5 min resulted in a dramatic increase in the number of TH-positive terminals throughout the brain, especially in the cerebellum, which contains fine preterminal and terminal axons that are difficult to stain. This pretreatment also led to a significant reduction in background staining and allowed for the use of the TH antiserum at high working dilutions. Several other proteolytic enzymes were tested and only chymotrypsin was nearly as effective as trypsin with respect to TH staining.     

Neuronal-glial interactions: Quantitation of astrocytic influences on development of catecholamine neurons

Effects of astroglia on the morphological and biochemical differentiation of catecholamine neurons from embryonic rat mesencephalon were studied in vitro, and compared to results obtained with fibroblasts. Neurite outgrowth and complexity were measured using computer-assisted morphometry on tyrosine hydroxylase immunoreactive neurons growing on preformed monolayers of astrocytes or fibroblasts. The morphological differentiation of these neurons was stimulated by the presence of astrocytes, and this effect was evident in various cellular compartments, including the size of the cell soma, length of neurites and neuritic segments, and the numbers of these segments. Tyrosine hydroxylase activity was measured biochemically in these cultures and was also found to be stimulated by the presence of astroglial monolayers. The implication of these results for the understanding of specific neuron-glial interactions during embryonic brain development is discussed.Special issue dedicated to Dr. Paola S. Timiras     

Proposed follow up programme after curative resection for lower third oesophageal cancer

Cyclins are indispensable elements of the cell cycle and derangement of their function can lead to cancer formation. Recent studies have also revealed more mechanisms through which cyclins can express their oncogenic potential. This review focuses on the aberrant expression of G1/S cyclins and especially cyclin D and cyclin E; the pathways through which they lead to tumour formation and their involvement in different types of cancer. These elements indicate the mechanisms that could act as targets for cancer therapy.