A silver-impregnation-toluidine blue technique for demonstration of embryonic skeletal structures in paraffin sections

Summary Dewaxed and hydrated sections are treated with 1% aq. silver nitrate in bright light for 60 min and then thoroughly washed with distilled water followed by a rinse in Kolthoff's buffer (pH 3.3). The sections are next treated with 0.25% toluidine blue dissolved in buffer for 3 min, rinsed in buffer, allowed to dry and then cleared and mounted. Foci of calcification appear black and cartilage-matrix lilac to deep mauve. Nuclei appear deep blue in contrast to the pale blue of the cytoplasm.     

A comparison of the rate of drying of four nematode species using a liquid paraffin technique

A technique of immersion refractometry has been employed to compare the rates at which four species of nematodes lose water during desiccation at 0% r.h. Panagrellus redivivus and Ditylenchus myceliophagus showed little ability to control water loss, although in the latter species coiling helped slow the rate of drying. Ditylenchus dipsaci and Anguina tritici exhibited a much greater degree of control over water loss during desiccation, A. tritici being more successful. D. dipsaci revived from ‘wool’ showed a marked decrease in ability to control water loss when compared with freshly extracted worms. The results obtained have been compared with those from work using interference microscopy, and a critical assessment of the liquid paraffin technique is presented.     

A simplified paraffin embedding method for small botanical samples

Abstract

We present a simplified paraffin embedding method suitable for unsuberized or unlignified small botanical samples (diameter < 0.3 cm). Only 2 h are required to yield plant tissues embedded in paraffin for anatomical observation and molecular analysis. Our method achieved morphological preservation of cell structures and conservation of nucleic acids that were equivalent to the traditional protocol. Fourier transform infrared spectrometry showed that the degree of degradation of the cytoplasmic components (e.g., protein) resulting from our simplified protocol was similar to that of the traditional protocol. The DNA samples embedded using the simplified method was extractable and could be used for PCR analysis. The DNA quality was equivalent to that embedded using the traditional method.     

Improvement in the specificity of the silver staining technique for AgNOR-associated acidic proteins in paraffin sections

Some recently developed silver staining methods allow selective staining of acidic nucleolar proteins. Pretreating deparaffinized sections with Schiff's reagent improves the specificity of Goodpasture and Bloom's AgNOR staining (as modified by Kodama et al.) after aldehyde fixation.     

A tissue adhesive for paraffin sections intended for deamination with sodium hypochlorite

Summary It has been found that sections of paraffin-embedded tissue attached to glass slides with a nitrocellulose-based adhesive instead of albumen retain their original morphology and integrity when deaminated with solutions of sodium hypochlorite.     

Use of paraffin bait technique in the isolation of Nocardia asteroides from sputum

Summary The use of paraffin bait technique in the isolation ofNocardia asteroides has been tested in 241 samples of sputa obtained from 235 cases of respiratory diseases.N. asteroides was recovered on 6 occasions from sputum of a patient using the paraffin bait technique. On the other hand cultures of sputa from the same patient on routine agar media such as Sabouraud's agar and Lowenstein Jensen medium yielded only one isolated of the pathogen.This work forms a part of the Ph. D. thesis of P.V.K. submitted to the University of Delhi.     

A reproducible technique combining tritiated thymidine autoradiography with immunodetection of bromodeoxyuridine for double labelling studies of cell proliferation in paraffin sections of tissues

A method is described to combine tritiated thymidine autoradiography with immunoperoxidase detection of bromodeoxyuridine on the same paraffin sections. It overcomes the varied technical artefacts we encountered when first attempting to combine these techniques and results in preparations with extremely low peroxidase and autoradiographic backgrounds. In particular, we find it is important to avoid the use of detergents during immunostaining, otherwise grain counts are reduced and autoradiograph exposures need to be greatly increased, and to avoid excessive peroxidase staining which makes it difficult to visualize silver grains in the overlying emulsion. The advantages of a method to remove emulsion films using acid-alcohol, allowing the same sections to be dipped twice with a long and a short autoradiographic exposure, are presented. The routine combination of high quality tritiated thymidine autoradiography with clean immunoperoxidase staining of bromodeoxyuridine-positive nuclei provides a new and powerful cell kinetic, double-labelling method to augment existing techniques e.g. by labelling the same cells undergoing DNA synthesis in successive cell cycles.     

A reproducible technique combining tritiated thymidine autoradiography with immunodetection of bromodeoxyuridine for double labelling studies of cell proliferation in paraffin sections of tissues

Abstract. A method is described to combine tritiated thymidine autoradiography with immunoperoxidase detection of bromodeoxyuridine on the same paraffin sections. It overcomes the varied technical artefacts we encountered when first attempting to combine these techniques and results in preparations with extremely low peroxidase and autoradiographic backgrounds. In particular, we find it is important to avoid the use of detergents during immunostaining, otherwise grain counts are reduced and autoradiograph exposures need to be greatly increased, and to avoid excessive peroxidase staining which makes it difficult to visualize silver grains in the overlying emulsion. The advantages of a method to remove emulsion films using acid-alcohol, allowing the same sections to be dipped twice with a long and a short autoradiographic exposure, are presented. The routine combination of high quality tritiated thymidine autoradiography with clean immunoperoxidase staining of bromodeoxyuridine-positive nuclei provides a new and powerful cell kinetic, double-labelling method to augment existing techniques e.g. by labelling the same cells undergoing DNA synthesis in successive cell cycles.