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W L Dunn

Publications and source records attributed to W L Dunn.

At least 37 records · Page 2Linked to original sources
PubMed1987

Histochemical procedures for the simultaneous visualization of neutral sugars and either sialic acid and its O-acyl variants or O-sulphate ester. II. Methods based upon the periodic acid-phenylhydrazine-Schiff reaction.

Four methods based upon the periodic acid-phenylhydrazine-Schiff reaction have been developed for the simultaneous visualization of neutral sugars with periodate oxidizable vicinal diols (hexose, 6-deoxyhexose, N-acetylhexosamine) and either sialic acids or side chain O-acyl sialic acids. In the first of these procedures, the saponification-periodic acid oxidation-2,4-dinitrophenylhydrazine-Azure A-Schiff-saponification (KOH-PA-DNPH-Az-KOH) method, all sialic acids stain Azure blue, neutral sugars with oxidizable vicinal diols stain yellow and mixtures of such components stain in various shades of green. In the second technique, periodic acid oxidation-2,4-dinitrophenylhydrazine-Azure A Schiff-saponification (PA-DNPH-Az-KOH), Azure Blue staining is confined to sialic acids without side chain substituents or which have an O-acyl substituent at position C7, while in the third method, the selective periodate oxidation-borohydride reduction-saponification-periodic acid oxidation-2,4-dinitrophenyl hydrazine-Azure A-Schiff-saponification (PA-Bh-KOH-PA-DNPH-Az-KOH) technique, only sialic acids with O-acyl substituents at positions C7, C8 or C9 (or which have two or three O-acyl side chain substituents) stain Azure blue. Finally in the fourth procedure, periodic acid oxidation-2,4-dinitrophenylhydrazine-Azure A-Schiff-saponification-borohydride reduction-periodic acid oxidation-Schiff (PA-DNPH-Az-KOH-Bh-PAS), sialic acids without side chain substituents or which have O-acyl substituents at C7 stain Azure blue, sialic acids substituted at position C8 or C9 (or which are di- or tri-substituted) stain magenta and neutral sugars stain yellow. Where mixtures of these components are present, a wide range of colours is obtained.

Animals↗
PubMed1987

Errors in longitudinal measurements of bone mineral: effect of source strength in single and dual photon absorptiometry.

The effect of changing strength during the useful life of a radiation source was evaluated in studies performed on four dual photon (DPA) and two single photon (SPA) bone absorptiometry instruments. Two DPA units and one SPA unit did not show any systematic dependence of measured bone mineral content or bone mineral areal density (BMD) on source activity when evaluated over an entire source life. One DPA and one SPA instrument, however, showed significant time trends associated with source activity. The fourth DPA instrument had a significant linear decrease in BMD over a source life in the automatic mode but performed better in the manual mode.

Bone and Bones↗
PubMed1986

Comparison of three platelet markers for measurement of platelet survival time in healthy volunteers.

We studied mean platelet survival times in healthy volunteers with use of [51Cr]disodium chromate, 111In-oxine (in a solution of acid-citrate-dextrose [ACD] and saline), and 111In-tropolone (in ACD-plasma) as markers. Differences found between the 51Cr and 111In labels probably can be attributed to a variation in localization of the label on the cell and of renal handling of the free label after release. The mean platelet survival time with 51Cr was slightly longer than the survival time with both indium labels and showed a sex difference not seen with 111In-oxine. Protein-bound plasma 51Cr was lower than plasma 111In and remained constant throughout the study. Plasma 111In increased with time. For survival time calculations, no correction for free 51Cr is necessary, but correction should routinely be performed when 111In markers are used. Both 111In markers gave similar results with respect to platelet survival time. The somewhat more elaborate plasma labeling procedure with tropolone shows no measurable advantage over the original 111In-oxine method. 111In-tropolone labeling takes less time and maintains platelets in the physiologic environment of plasma during incubation. Biodistribution studies show no difference between the two 111In markers.

Blood Platelets↗
PubMed1985

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. III. Changes in the histochemical and chemical properties of the epithelial glycoproteins in the mucosa close to colonic tumours.

Histochemical, chemical and histological studies were performed on 26 specimens of human colonic tumours and 62 specimens of mucosa taken at distances of 0.5-5.0 cm from the tumour. The tumour glycoproteins were divided almost equally between three anionic types, sulphomucin, sialomucin and mixed sialomucin and sulphomucin. All showed a reduction in staining for side chain O-acylated sialic acid. In 56% of the tumours, this was accompanied by loss of glycoprotein while, in 44%, abundant mucin was still present. Histochemical examination of the mucosal specimens indicated that in 24.2% the side chain O-acylated sialic acids did not differ from normal. In 41.9% there was a focal change and in 33.9% there was a generalized field reduction in the proportion of side chain O-acyl sialic acids. The latter were subdivided into moderate and severe. Chemical analyses correlated well with the histochemical classification of the mucosal specimens and showed that, on average, the classifications focal and severe field change were not due to sampling error. Forty-five per cent of the cases showed only focal change and 40% only field change. Mucosal specimens associated with 60% of the moderately differentiated tumours showed only focal change while those associated with 75% of well-differentiated tumours showed only field change. Abnormal patterns of staining for side chain O-acylated sialic acids (a) were largely independent of the distance from the tumour, (b) occurred in the presence of a normal pattern of staining for sialomucins and sulphomucins and (c) were associated with 61.4% of the specimens that showed no discernible evidence of histological abnormality. In contrast, only one specimen showed evidence of histological change without a corresponding change in O-acylated sialic acids. The data suggest that abnormal patterns of staining for O-acylated sialic acids may represent premalignant change but their precise significance and specificity requires further studies of non-neoplastic diseases of the colon.

Colonic Neoplasms↗
PubMed1985

Chemical and histochemical studies of normal and diseased gastrointestinal tract. IV. A comparison of histochemical and chemical methods for the estimation of side chain O-acylated sialic acids.

Statistically significant correlations were obtained between a chemical assay for the proportion of colonic epithelial glycoprotein sialic acids with side chain O-acyl substituents and two histochemical methods, the PBT-KOH-PAS sequence (rs = 0.7485 for N = 31, P = 0.01, one-sided test) and the PAPT-KOH-Bh-PAS procedure (rs = 0.7024 for N = 34). A positive correlation (rs = 0.8654 for N = 30, P = 0.01) was also obtained between the results of the two histochemical procedures. It is concluded that, on average, histochemical observations are a reliable semiquantitative comparative method for the estimation of side chain O-acetylated sialic acids.

Colon↗
PubMed1985

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. V. A differential diagnostic method for the histochemical classification of glycoproteins.

A differential diagnostic scheme is described for the division of colonic epithelial glycoproteins into eleven histochemically distinct classes. The scheme depends upon the use of seven histochemical techniques which, collectively, permit the differential staining of O-sulphate ester, sialic acid and its side chain O-acyl variants and vicinal diols located on carbohydrate residues other than sialic acids. Elements of the scheme also provide a general approach to the classification of epithelial glycoproteins in anatomic sites other than the colon. Application of the scheme permitted the classification of the epithelial glycoproteins in the mucosa 0.5-5.0 cm from human colonic tumours and provided direct confirmation of previous observations that changes from normal in the relative proportions of either side chain O-acylated sialic acids or sialic acids and O-sulphate esters can occur independently of one another.

Colonic Neoplasms↗
PubMed1985

Dual-photon Gd-153 absorptiometry of bone.

Dual-photon absorptiometry with gadolinium 153 was used to measure the mineral content of lumbar vertebrae in cadavers, excised vertebrae with marrow, and dry, marrow-free vertebrae. The error introduced by the surrounding soft tissue of cadavers was 3%, and the error in determining mineral mass or density in excised vertebrae was about 5%. The correlation coefficient between the results of Gd-153 and corrected iodine 125 (single-photon) absorptiometry on 24 femoral necks was 0.99, and the predictive error was 3.7%. Dual-photon absorptiometry accurately indicates bone mass and bone density and is only slightly affected by either surrounding tissue or fat changes in bone marrow.

Bone Marrow↗
PubMed1985

Performance evaluation of xenon-133 inhalation rebreathing systems for regional blood flow measurements.

A quality-control phantom is described which is capable of testing the performance of inhalation rebreathing systems for measurements of regional cerebral blood flow (rCBF). The phantom is designed so that data similar to those from a patient study are obtained. The standard rCBF data-processing algorithm is used for the calculation of phantom study results. Malfunctions were induced to simulate instrument malfunction, and their effects on detector and air curves were evaluated. The use of this phantom is recommended prior to a patient study if the rCBF instrument is used infrequently or after service for routine maintenance or malfunction.

Cerebrovascular Circulation↗
PubMed1984

Polyarthritis associated with gastric carcinoma.

In a 68-year-old man who had polyarthritis associated with gastric carcinoma surgical resection of the tumour was accompanied by prompt resolution of the arthritic syndrome. In 11 years of follow-up the arthritis has remained in complete remission and there has been no recurrence of the carcinoma. An awareness that polyarthritis may be a presenting manifestation of an underlying carcinoma may, especially in an elderly person, lead to early recognition and treatment of the malignant disease.

Adenocarcinoma↗
PubMed1984

Role of anions in the lymphocytolytic action of corticosteroids and fatty acids.

Rat thymocytes were exposed in vitro to the corticosteroid dexamethasone, 10 nM, for 10 min, or to oleic acid, 500 nM for 2 min. This results in cytolysis after 6 hr, if incubation is continued. Instead, the cells were centrifuged, the supernatant fluid decanted, and the cells subjected to osmotic shock in 1.5 mM MgCl2. The naked nuclei were incubated at 37 degrees C and examined by light and electron microscopy. Nuclear edema was evident early, and most nuclei showed damage with variation in shape and size and distinct folds, which was maximal by 1-2 hr as a result of these treatments. This was true also if nuclei were incubated in MgF2 or Mg(NO3)2 but not in MgBr2, MgI2, MgSO4 or Mg-citrate. Spleen lymphocyte nuclei showed similar damage but only after incubation with 20 microM oleic acid, and not at all with corticosteroids. The effects of both steroid and fatty acid, even at greatly increased concentrations, were inhibited by tri-n-butyl tin chloride, 10 microM, and by 4-4'-diisothiocyanostilbene-2,2'-disulfonic acid, sodium salt, 10 microM, both of which block chloride ion transport. It is concluded that the cytolytic effects of both corticosteroids and free fatty acids involve influx of chloride ion resulting in nuclear edema, which subsequently leads to fragmentation of chromatin, karyorrhexis and, ultimately, cytolysis.

Animals↗
PubMed1984

Histochemical identification of side chain substituted O-acylated sialic acids: the PAT-KOH-Bh-PAS and the PAPT-KOH-Bh-PAS procedures.

Two new methods, based on the original periodic acid-Thionin Schiff-saponification-periodic acid-Basic Fuchsin Schiff (PAT-KOH-PAS) technique of Culling et al. (1976), have been devised for the histochemical identification of side-chain O-acylated sialic acids. In the first of these, the periodic acid-Thionin Schiff-saponification-borohydride reduction-periodic acid-Basic Fuchsin Schiff (PAT-KOH-Bh-PAS) procedure, the specificity of the original PAT-KOH-PAS technique was improved by: (a) extending, when necessary, the initial period of periodate oxidation, (b) increasing the period of exposure to Thionin Schiff reagent from 30 min to 4 h, (c) using a Thionin Schiff reagent prepared by a different method, (d) interposing a borohydride reduction step between the saponification and PAS steps and, (e) extending the period of oxidation in the final PAS step from 10 to 30 min. In the second procedure, the periodic acid-phenylhydrazine-Thionin Schiff-borohydride reduction-periodic acid-Basic Fuchsin Schiff (PAPT-KOH-Bh-PAS), based on the periodic acid-phenylhydrazine-Schiff (PAPS) technique of Spicer (1961), blue Thionin Schiff staining was confined to sialic acid residues with oxidizable side chain vicinal diols by interposing a treatment with 0.5% (w/v) aqueous phenylhydrazine hydrochloride for 2 h at room temperature between the initial periodic acid oxidation and the Thionin Schiff steps of the PAT-KOH-Bh-PAS procedure. These procedures are discussed within the general framework of the methods available for the histochemical identification of side-chain O-acylated sialic acids.

Animals↗
PubMed1984

Histochemical studies of the mechanism of the periodic acid-phenylhydrazine-Schiff (PAPS) procedure.

Histochemical investigations of the periodic acid-phenylhydrazine-Schiff (PAPS) procedure were carried out on tissues containing carbohydrate macromolecules known to produce on periodate oxidation, only sialic acid monoaldehydes or hexosedialdehydes or mixtures of the two. The results indicated that the PAPS reaction is a generalized phenomenon independent of the hydrazine or hydrazide used, the nature of the Schiff reagent or the presence of anionic groups. It is proposed that phenylhydrazine condenses with periodate-engendered sialic acid monoaldehydes to yield the corresponding phenylhydrazone and with periodate-engendered dialdehydes to yield the corresponding morpholine or azido derivatives. Subsequent Schiff treatment results in the reversal of the blockade of sialic acid monoaldehydes but not of the dialdehydes, thus leading to selective Schiff staining of sialic acid residues.

Aldehydes↗
PubMed1984

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. I. A comparison between histologically normal colon, colonic tumours, ulcerative colitis and diverticular disease of the colon.

Chemical and histochemical methods were used to compare the epithelial glycoproteins from formalin-fixed surgical specimens of normal human large intestine, colonic tumours, ulcerative colitis and diverticular disease. All the epithelial glycoproteins contained fucose, galactose, glucosamine, galactosamine and, in addition, sialic acids both with and without O-acyl substituents in the side chain and/or at position C4. The glycoproteins of the normal ascending and descending colons differed significantly with respect to the percentage of the sialic acids released following digestion of the de-O-acylated glycoprotein with Vibrio cholera neuraminidase and to the molar fucose-sialic acid ratio. Statistical analysis of the chemical data showed that (a) compared to normal, the sialic acids of the tumour and ulcerative colitis glycoproteins from the descending colon were significantly less substituted in the side chain and at position C4; (b) the O-acetyl substitution pattern of the sialic acids of the ulcerative colitis glycoproteins from the ascending colon and the quantitative composition of the carbohydrate prosthetic groups of the ulcerative colitis glycoproteins from both ascending and descending colons differed from normal; (c) it was not always possible to distinguish between the ulcerative colitis and tumour glycoproteins on the basis of the O-acetyl substitution pattern of their sialic acids; and (d), there were minor differences between normal glycoproteins and those from cases of diverticular disease.

Colitis, Ulcerative↗
PubMed1984

Chemical and histochemical studies of normal and diseased human gastrointestinal tract. II. A comparison between histologically normal small intestine and Crohn's disease of the small intestine.

Comparative chemical and histochemical studies were performed on formalin-fixed, surgical specimens of human small intestine from cases of Crohn's disease and normal controls. The sialic acids of the crude glycoproteins isolated from normal ileum were significantly less neuraminidase-susceptible and more C4 substituted (P less than 0.01) than those of the glycoproteins isolated either from normal upper small intestine (duodenum and jejunum) or from cases of Crohn's disease of the ileum. Fractionation yielded two major sialic acid-containing fractions, eluting from DEAE-cellulose with 0.2 M or 0.3 M sodium chloride. Both fractions contained fucose, galactose, glucosamine and galactosamine in addition to sialic acids both with and without O-acyl substituents at position C4 and/or in the side-chain (side-chain O-acylated sialic acids were also detected by histochemical procedures). The fractions differed significantly from one another with respect to the neuraminidase susceptibility of their sialic acids (P less than 0.01), the percentage of C4 (P less than 0.01) and side-chain substituted sialic acids (P less than 0.05), and the molar fucose-sialic acid ratio (P less than 0.05). The O-acyl substitution patterns of the sialic acids of both the 0.2 M and 0.3 M fractions of the upper small intestine glycoproteins differed significantly from those of the corresponding fractions from normal ileum, while the sialic acids of the 0.2 M fractions from Crohn's disease of the ileum differed significantly from normal with respect to neuraminidase susceptibility (P less than 0.01) and percentage C4 substitution (P less than 0.01); the 0.3 M fractions differed only in the percentage of sialic acids substituted at C4. The differences between the sialic acids from the normal and Crohn's disease specimens were shown to be independent of either the anatomical origin of the specimen or the histopathological sub-group of the Crohn's disease specimens; no significant differences were noted between the sub-groups but all the sub-groups differed from normal.

Crohn Disease↗