Basic and applied histochemistry最新文献

The uptake of different concentrations of (2.5-3H) histamine by normal human neutrophils at 37.5 degrees C in a tris-albumin buffer was determined at 20, 60 and 90 min of incubation. Uptake was correlated with the concentration of amine and incubation time with a saturation-like curve. On the basis of these results, it is suggested that neutrophils play a role in the regulation of histamine plasma levels.

The authors report on the activity of Hinf I restriction endonuclease on human fixed metaphase chromosomes. Experiments performed by digesting chromosomes just after harvesting or after ageing in methanol-acetic acid displayed a different pattern of digestion on metaphases, since only aged preparations showed gaps on heterochromatic regions of chromosomes 1, 9 and 16 and C-like bands on other chromosomes. In this view, the authors suggest that structural modifications of the DNA, induced by acid fixation, can influence Hinf I activity on fixed metaphase chromosomes.

Immunohistochemical demonstration of S-100 protein in Langerhans cells (LCs) was made in odontogenic epithelial tumours (71 cases), radicular cysts (40 cases), follicular cysts (28 cases), odontogenic keratocysts (11 cases), primordial cysts (7 cases) and fissual cysts (6 cases). With the use of polyclonal antiserum against S-100 protein, positive LCs, dendrical or irregular in shape were found in tumour or cystic epithelia, and sometimes in stromal connective tissue. Incidence of positive S-100 staining LCs was 11 cases out of 61 ameloblastomas, 22 cases out of 40 radicular cysts, 3 cases of 28 follicular cysts, and other lesions in both odontogenic tumours and cystic diseases lacked LCs. The cases with S-100 protein positive LCs were usually accompanied with a high degree of inflammatory infiltration in their lesions; on the contrary, the negative cases also generally lacked inflammatory responses.

A non-specific staining of mast cells by a number of proteins and immunoglobulins has been observed using different immunocytochemical techniques and different antisera at light and electron microscopy level. This finding has been related to an ionic binding of cationic charges, such as aminic groups with an high pI, to the strongly anionic residues of mast cell granules. This hypothesis is supported by the lack of non-specific binding achieved using negatively charged chromogens (i.e. FITC--or Rhodamine-conjugated antibodies) or using cationic dyes before the immunohistochemical reaction. It is therefore stressed that adequate and accurate negative controls must always be carried out in order to get correct interpretations of the staining results.

Two methods have been used to determine the isobestic (equiconcentration) wavelength of formazans derived from nitroblue tetrazolium-succinate dehydrogenase (EC 1.3.99.1) activity in cryostat sections of the rat superior cervical ganglion prior to microdensitometric measurements. Both methods indicate that maximal absorbance of the final reaction product is at a wavelength of 540-550 nm. This wavelength differs by 35-45 nm from that used to measure the same reaction product in sections of other rat tissues such as liver and implies that it may be unwise to adopt a "standard" wavelength for a particular reaction product when making microdensitometric measurements in relation to quantitative enzyme histochemistry.

Lymphokine activated killer (LAK) cells have been utilized as a useful tool in cancer adoptive immunotherapy. The lineage origin of this population has always been controversial since it shares phenotypic markers with both myelomonocytic cells and T lymphocytes. Recently we described a new monoclonal antibody (MoAb), termed LAK1, which recognizes a 120 Kd surface molecule expressed on human large granular lymphocytes (LGL) and LAK precursors and effectors. LAK1 MoAb defines two different populations of positive cells amongst peripheral lymphocytes: the first subset (20%), represented by brightly stained cells, belongs to the non T-LGL population, whereas the second subset (30%) displays low fluorescence intensity and was partially composed of T lymphocytes. More interestingly, LAK1 is shared by some other cell types, such as monocytes and vascular endothelial cells. Immunohistochemical staining performed on muscle, endometrium and lymphoid or other non lymphoid tissues shows that LAK1 antigen is selectively expressed by the reticuloendothelial system.

Presence of pericellular basket-like network of fibres immunoreactive to substance P and to calcitonin gene-related peptide is shown around non-immunoreactive primary sensory neurons of human trigeminal ganglion. Single neurons can be wrapped by either peptide-containing fibres or by both. Such pericellular structures might represent sites of interneuronal communications at ganglionic level.

In order to search for a new staining agent with higher selectivity for particular metals, the ability of fluorone derivatives to histochemically stain metals present in rat tissues was examined. Among a variety of metals tested, phenylfluorone showed intense staining only for tin. The phenylfluorone method was superior to the conventional gallein method with regard to selectivity when staining for tin among various metals in histochemical practice.

Enriched fractions of neuronal and glial cells from rat and human (autoptical specimens of frontal cortex) brains were assayed for thiaminpyrophosphatase (TPPase) activity by isoelectric focusing (IEF). Glial and neuronal fractions yielded about 0.16 and 0.03 g/g of wet tissue respectively. Purity was estimated to be 85-90%. The isolated fractions were homogenized in the presence of 1% Triton X-100, and IEF was carried out on thin layer polyacrylamide gel in a pH range of 3.5-9.5, using Ampholine PAG plates. TPPase activity of the protein bands was assayed by laser-densitometry, after incubation with thiaminpyrophosphate in an appropriate buffer and PbS staining. IEF analysis showed that TPPase activity was present almost exclusively in the neuronal fraction (at levels 16-fold higher than those found in the glial fraction). After IEF, TPPase activity was present in 10 distinct protein bands with different isoelectric points. These preliminary data suggest that TPPase may be involved in the neuronal activity of rat and human brain.