Biomedical subjects

J M Lucocq

Publications and source records attributed to J M Lucocq.

39 records · Page 3Linked to original sources

PubMed1984

Applications of immunocolloids in light microscopy. III. Demonstration of antigenic and lectin-binding sites in semithin resin sections.

Previous studies have demonstrated that antigens or lectin-binding sites can be localized in sections from paraffin-embedded tissues with protein A or lectins bound to colloidal gold or colloidal silver (Roth J: J Histochem Cytochem 30:691, 1982 and 31:547, 1983). In the present study the protein A-gold technique and lectin-gold complexes have been applied to semithin sections (0.5-1.5 micron) of Epon- or low temperature Lowicryl K4M-embedded rat pancreas, kidney and submandibular gland. The results show that an increase in resolution and, therefore, in amount of information can be obtained. The optimal mode of imaging was determined on sections without counterstaining. Bright-field illumination gives the maximum information about the staining signal, while phase-contrast and Nomarski differential interference contrast give predominantly structural and, to a lesser extent, staining information. Polarization epi- and transillumination microscopy is inferior in all aspects. The application of a battery of lectin-gold complexes to rat submandibular gland revealed a specific staining pattern for each lectin in acinar and excretory duct cells.

Animals↗

PubMed1984

Light and electron microscopic demonstration of sialic acid residues with the lectin from Limax flavus: a cytochemical affinity technique with the use of fetuin-gold complexes.

The development of a cytochemical affinity technique for the demonstration of sialic acid residues by light and electron microscopy is reported. The lectin from the slug Limax flavus, with its narrow specificity for N-acetyl- and N-glycolylneuraminic acid, was applied to tissue sections. Subsequently fetuin-gold complexes were used to visualize the tissue-bound lectin. Different cytochemical controls, including sugar inhibition tests, neuraminidase digestion, the use of fetuin-gold complexes alone, or acid hydrolysis of sections, proved the specificity of the technique. Postembedding staining was performed on frozen, paraffin, or semithin resin sections for light microscopy and on thin sections from low temperature Lowicryl K4M-embedded material for electron microscopy. The distribution of sialic acid residues in rat pancreas, liver, and colonic mucosa was investigated.

Animals↗

PubMed1981

Islet organ, blood glucose and glucose tolerance of lean and obese Mongolian gerbils. A quantitative study.

Gerbils were divided, on the basis of body weight, into obese (greater than 80 gms) and lean (less than 80 gms) groups. Fasting blood glucose estimations on all 31 gerbils, and glucose tolerance tests on 9 lean and 6 obese animals, were carried out. All lean and some obese gerbils were normoglycaemic and other obese were hyperglycaemic. All obese gerbils exhibited glucose intolerance. General morphological studies were undertaken as follows: (i) assessment of mesenteric fat deposits, (ii) measurement of anterior abdominal wall thickness, (iii) ratio of animal length to width at specified loci (index of shape). The degree of obesity was less than previously reported in this species though blood glucose abnormality was comparable. The index of animal shape showed a strong correlation with body weight. The following kinds of histological observation were made on pancreases from 4 lean and 4 obese gerbils: (i) % islet representation, (ii) islet size distribution, (iii) beta-cell granularity, (iv) islet vascularity, (v) islet/duct association, (vi) proportions of alpha- and D-cells, (vii) glycogen deposition in islet and duct cells. The pancreases of obese gerbils contained a higher proportion of islet tissue than those of lean due to generally larger islets: this hyperplasia was mainly attributable to beta-cell proliferation. Many obese gerbil islets exhibited hyperaemia and beta-cell degranulation. There was no evidence of glycogen deposition.

Animals↗