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Biomedical subjects

H Lyon

Publications and source records attributed to H Lyon.

At least 37 records · Page 2Linked to original sources
PubMed1984

Microtechniques for flow cytometric analysis of aqueous humor lymphocytes.

Flow cytometric analysis of monoclonal antibody labelled lymphocytes is an important tool in understanding the immune response. Microtechniques were developed to analyze lymphocytes in small amounts of ocular fluids. Optimal labelling volumes and concentrations for Leu 2a, Leu 3a, Leu 4 and Leu M3 antibodies were determined. The ability to label and reproducibly analyze cell samples with as few as 1000 cells is demonstrated.

Antibodies, Monoclonal↗
PubMed1984

Preparation and characterization of methyl green tetrafluoroborate.

Commercial methyl green dyes were converted to tetrafluoroborate by means of NaBF4-solution, the compounds thus obtained were analytically pure. It was shown to be possible to distinguish between a "methyl" and an "ethyl" compound by means of NMR spectroscopy. The dyes are stable in buffered aqueous solution, and in crystalline form. A spectrophotometric assay is proposed.

Borates↗
PubMed1984

Spectrophotometric characteristics and assay of pure pyronin Y.

The spectrophotometric characteristics of analytically pure pyronin Y have been investigated. Addition of metal ions (Fe3+, Zn2+, and Mg2+) and of dextrin were shown not to influence the absorption characteristics. The composition of the solvent strongly influenced the value of the extinction coefficient. Aqueous ethanolic solutions with a content of about 50% ethanol gave higher epsilon-values than those found for more concentrated ethanol solutions. The difference can be explained by the existence of a solvent-solute complex in the less concentrated ethanol solutions. A new spectrophotometric assay is proposed using the epsilon-value 11.7 X 10(4) lmol-1 cm-1 found in aqueous ethanol (52%) as standard.

Iron↗
PubMed1983

Antiretinoblastoma monoclonal antibodies.

Mouse-mouse somatic hybridization techniques were used to produce monoclonal antibodies directed towards antigen expressed on retinoblastoma-derived tissue culture cell lines. Four monoclonal antibodies were produced with varying avidity which were reactive against allogeneic retinoblastoma-associated antigens. Sensitivity and specificity was demonstrated using ELISA and chromium release assays. Immunofluorescent antibody studies suggest that these monoclonal antibodies may be useful diagnostically.

Animals↗
PubMed1982

Purity of commercial non-certified European samples of Pyronin Y.

The purity of six European non-certified samples of Pyronin Y was compared with that of two American samples certified by the Biological Stain Commission. The methods used were spectrophotometry and a Methyl Green-Pyronin staining test (both as applied by the Biological Stain Commission), thin layer chromatography, mass spectrometry, determination of pH, and content of some electrolytes. It was found that none of the European batches of Pyronin Y passed the complete test as prescribed by the Biological Stain Commission. Their dye content was uniformly low (between 5 and 19%). Furthermore, thin layer chromatography and mass spectrometry revealed that two of the dye samples contained no Pyronin Y or only traces. It is concluded that assessment of an unknown sample of a dye labelled Pyronin Y should be initiated with thin layer chromatography. The pH and content of electrolytes in an aqueous solution of the dye should also be determined in order to obtain reproducible staining results. Finally, the value of the work performed by the Biological Stain Commission is underlined, although more sophisticated methods are necessary for testing the purity of dyestuffs.

Cations↗
PubMed1982

Endocrine cells and melanin-containing cells in the anal canal epithelium.

The epithelium of the anal canal from 22 humans was studied in order to demonstrate the possible presence of endocrine cells and melanin-containing cells. Histochemical methods aimed at demonstrating reducing substances, biogenic amines, argyrophilia and melanin, were used. Enterochromaffin cells, and possibly other types of endocrine cells, were demonstrated above the dentate line both in colo-rectal type epithelium and in the anal transitional zone. Melanin-containing cells could also occasionally be found in the anal transitional zone. The presence of endocrine cells in the anal canal epithelium opens up the possibility that carcinoids can originate in this region. Further, the presence of melanin-containing cells might explain the occurrence of malignant melanomas arising above the dentate line.

Adenocarcinoma↗
PubMed1982

The effect of D-penicillamine and methylprednisolone on the morphology of experimental granulation tissue in rats.

The effects of D-penicillamine and methylprednisolone on the formation of granulation tissue was studied in rats with Visella-sponge induced granulation tissue after 42 days of treatment. D-penicillamine in doses of 20 mg-, 100 mg-, 500 mg/kg/day caused no morphological differences compared with the control groups as regards ingrowth of granulation tissue and its content of collagen fibres, inflammatory cells, vessels and glycosaminoglycans. Treatment with methylprednisolone, 0.2 mg-, 2.0 mg-, and 5.0 mg/kg/day caused a dose dependent reduction in the ingrowth of granulation tissue. Methylprednisolone caused a reduction in the number of fibroblasts and collagen fibres, but no differences in the content of glycosaminoglycans could be demonstrated between the treated and the control groups. Granulation tissue produced during combination treatment with D-penicillamine 100 mg and methylprednisolone 2.0 mg/kg/day did not differ from that observed after methylprednisolone treatment alone. Thus, only high doses of methylprednisolone gave rise to an antiinflammatory action in this morphological study on granulation tissue, whereas D-penicillamine had no effect within the present dose interval. The quantitative alterations are in agreement with parallel biochemical analyses. However, the inhibitory effect of D-penicillamine on collagen crosslinking was not associated with light microscopic changes in the ultrastructure of the collagen fibres.

Animals↗
PubMed1982

Fibronectin in experimental granulation tissue.

The temporal appearance of fibronectin in experimental granulation tissue has been studied using the immunoperoxidase technique on material fixed in formaldehyde, embedded in paraffin and pretreated with pepsin. Furthermore, the relationship between the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by the van Gieson method, has been investigated. Fibronectin was demonstrated as part of the fibrinous network in the sponge before the formation of granulation tissue. In the development of granulation tissue fibronectin was seen in the initial cellular stage codistributed with the newly formed fibres, first the argyrophilic fibres and later with those stained red by the van Gieson method, too. With maturation of the granulation tissue, predominated by these fibres, the amount of fibronectin was gradually reduced. The presence of fibronectin in the sponge already before the formation of granulation tissue suggests that fibronectin in the initial stage of inflammation derives from plasma. The increase in amount of fibronectin corresponding to the cellular (fibroblastic) proliferation and the formation of fibres, both argyrophilic and van Gieson positive, indicates that fibronectin in young granulation tissue is synthesized by fibroblastic cells. The relationship between the morphologically demonstrated argyrophilic fibres and van Gieson positive fibres and the biochemical type III and type I collagens is discussed.

Animals↗
PubMed1981

Isolation of Mallory bodies and an attempt to demonstrate cell mediated immunity to Mallory body isolate in patients with alcoholic liver disease.

Mallory bodies were isolated from necropsy livers from patients with alcoholic hepatitis with and without cirrhosis with a Ficoll viscosity barrier. The purity of Mallory bodies in the isolate varied between 70 and 90%, estimated by counting Mallory bodies and non-Mallory body structures in haematoxylin-eosin stained smears. Electron microscopy confirmed the presence of Mallory bodies in the isolates. The Mallory body isolate was used as antigen in the agarose leucocyte migration inhibition test in order to test the cell-mediated immunity. No significant difference in leucocyte migration was found between controls and patients with alcoholic hepatitis, alcoholic steatosis, alcoholic cirrhosis and miscellaneous liver diseases.

Adolescent↗
PubMed1981

Method for direct induction of serotonin fluorescence in a carcinoid tumor after embedding in hydroxyethyl methacrylate.

Tissue slices from a carcinoid tumor were fixed in formalin and after dehydration embedded in hydroxyethyl methacrylate. Sections, 5 micrometers in thickness, were cut with a D-knife mounted on a serial microtome. Some sections were stained with either hematoxylin and eosin or by azo-coupling with fast garnet GBC, whereas others were reacted for catecholamines and indolamines either by exposing them to formaldehyde vapor for 1 hour at 80 degrees C. or by dipping them into a sucrose-phosphate buffer-glyoxylic acid solution followed by heating at 80 degrees C. for 15 minutes. Fluorescence intensities and the spectra of the fluorophores were recorded on 5-micrometers thick formaldehyde-reacted sections by microspectrofluorometry. With both the formaldehyde vapor method and the glyoxylic acid solution method, an intense yellow fluorescence was obtained from the carcinoid tumor cells, as well as from normal enterochromaffin cells. The excitation and emission maxima obtained by microspectrofluorometry from these cells indicated the presence of a fluorophore originating from serotonin.

Acrylates↗
PubMed1980

Aldehyde Fuchsin staining of pancreatic B cells. Reproducible high-contrast staining of formalin-fixed and paraffin-embedded material.

The use of Aldehyde Fuchsin for the demonstration of B cell granules in the pancreatic islets on material fixed in formalin and embedded in paraffin has led to variable results. Treatment of such sections for 1 h with Bouin's fluid or 5% glutaraldehyde prior to deparaffinization, however, stabilizes the secretory granules in B cells. In addition, the zymogenic granules of the acinar cells exhibit increased stainability with the permanganate Aldehyde Fuchsin procedure.

Animals↗