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W Galbraith

Publications and source records attributed to W Galbraith.

At least 37 records · Page 2Linked to original sources
PubMed1989

Design and synthesis of conformationally restricted phospholipids as phospholipase A2 inhibitors.

The use of conformationally restricted phospholipids 1 and 2 has been employed to understand the conformational preference of phospholipase A2 (PLA2) for substrate phospholipids. Inhibition of porcine pancreatic PLA2 with 1 and 2 indicated a two- to fivefold preference for the distal isomer 2 over the proximal isomer 1. Based upon these studies, both side-chains of the substrate phospholipid appear to occupy the lipid binding domains near the active site with the side-chains further apart most preferred by PLA2.

Animals↗
PubMed1989

Topical anti-inflammatory activity of DuP 654, a 2-substituted 1-naphthol.

Recent work suggests that one of the common biochemical characteristics of skin inflammatory diseases such as psoriasis is altered arachidonic acid metabolism with elevated levels of prostaglandins and leukotrienes. DuP 654, a 2-substituted 1-naphthol, is an exceptionally potent inhibitor of 5-lipoxygenase. DuP 654 was tested in various models of skin inflammation and was found to be potent at inhibiting edema induced by the topical application of arachidonic acid, tetradecanoyl phorbol acetate or the calcium ionophore A23187. DuP 654 was also effective in a murine model of contact sensitivity. DuP 654 was effective at reducing the numbers of infiltrating polymorphonuclear leukocytes in AA and TPA induced edema. These data, taken together, suggest that DuP 654 may be effective in treating human skin diseases.

Administration, Topical↗
PubMed1989

Phospholipase A2 (PLA2) activity in undifferentiated U937 cells.

PLA2 activity has been described in U937 cells. The present study characterized PLA2 activity in these undifferentiated cells. Cells were grown in suspension culture, harvested by centrifugation, and washed and homogenized in a neutral buffer containing standard proteinase inhibitors. A low speed supernatant was fractionated either by acid extraction or by sucrose density gradient centrifugation. PLA2 activity was measured using either L-alpha-1-palmitoyl-2-arachidonoyl[1-14C]-phosphatidylcholine or heat-inactivated [3H]oleic acid-labeled E. coli as substrates. Substrate-specific PLA2 activity was found in the acid-extracted and in the 25% sucrose fractions. Standard inhibitors were investigated with these PLA2 activities. Our results suggest undifferentiated U937 cells contain three distinct PLA2 activities. This is the first indication that more than one PLA2 activity is present in undifferentiated U937 cells.

Escherichia coli↗
PubMed1987

Effect of antiinflammatory drugs on human interleukin-1-induced cartilage degradation.

Human monocyte IL-1 stimulated the release of proteoglycans from cartilage in organ culture in a concentration-related manner. This stimulation required protein synthesis as shown by inhibition with cycloheximide. The metal chelator, 1,10-phenanthroline, inhibited breakdown, suggesting the involvement of a metalloproteinase. Various nonsteroidal anti-inflammatory drugs (100 microM), and the corticosteroids, dexamethasone and hydrocortisone (1-10 microM), were not effective in blocking proteoglycan release. Of the disease modifying agents tested, levamisole was ineffective while the antimalarials, chloroquine (100 microM) and hydroxychloroquine (100 microM), inhibited the action of IL-1. The free-radical inhibitor SOD (5000 U/ml but not 1000 U/ml) was effective while catalase (8000 U/ml) was not. The protective effects of SOD and the antimalarials suggest that oxygen reactive species may play a role, while lack of inhibition with NSAIDs and corticosteroids indicate that arachidonic acid metabolites may not be important in this degradative process.

Animals↗
PubMed1985

A survey of transforms of the CIE 1931 chromaticity diagram with some new non-linear transforms and histological illustrations of their utility.

Surveys are presented of the published data on colour matching, and of the published transforms of the CIE 1931 chromaticity diagram. All transforms are given in the form of standardized equations and tables of coefficients. Both linear and non-linear transforms are considered, although the latter are given special attention. The concept of a uniform chromaticity space (UCS) is discussed, and the published transforms are assessed for uniformity using the colour matching data. 2 series of new, non-linear transforms are presented, both based on 2-dimensional polynomial equations, and both derived using iterative optimization techniques. The 1st series attempts to approximate Farnsworth's (1961) diagram. The 2nd uses Nutting's colour matching points directly. The coefficients of these transforms are tabulated. It was found that increasing the number of coefficients in the 2-dimensional polynomial, beyond 15 each for x and y, does little to increase the uniformity of the resulting transform. The usefulness of UCS's in assessing stain performance is illustrated by examples drawn from the areas of azure B/eosin staining of blood cells and Papanicolaou staining of epithelial cells from the uterine cervix.

Blood Cells↗
PubMed1985

Colorimetry for the stain technologist. IV. Analysis of the components of color difference.

Total color differences have been calculated for various pairs of stained microscopic substrates. The latter include azure B/eosin stained blood cells and Papanicolaou stained cells from the uterine cervix. Both the CIE L*u*v* and L*a*b* color spaces have been used. Total color differences have been analyzed in terms of lightness, hue and chroma components. Various discrepancies have been noted among these components, especially the chroma difference, for the two spaces. It is concluded that current color-difference formulae are less than perfect, although they can provide much useful information.

Azure Stains↗
PubMed1984

Microspectrophotometric studies of Romanowsky stained blood cells. III. The action of methylene blue and azure B.

The performances of two standardized Romanowsky stains (azure B/eosin and azure B/methylene blue/eosin) have been compared with each other and with a methylene blue/eosin stain. Visible-light absorbance spectra of various hematological substrates have been measured. These have been analyzed in terms of the quantities of bound azure B, methylene blue and eosin dimers and monomers, and in terms of the CIE color coordinates. It has been found that the addition of methylene blue to azure B/eosin produces little change in performance, at least using these two analytical methods. Methylene blue/eosin does not produce the purplish colorations typical of the Romanowsky effect. This is due not to differences between the spectra of methylene blue and azure B, but to the fact that methylene blue does not facilitate the binding of eosin to cellular substrates to the same extent as azure B.

Azure Stains↗
PubMed1984

Microspectrophotometric studies of Romanowsky stained blood cells. IV. Maturation of myeloid and erythroid cell lines in bone marrow.

A quantitative characterization has been made of azure B/eosin stained cells from bone marrow. Two cell lines were followed: the myeloid line (white cell blast, promyelocyte, neutrophilic myelocyte, neutrophilic metamyelocyte, neutrophilic band, neutrophilic segmented) and the erythroid line (rubriblast, prorubricyte, rubricyte, metarubricyte, diffusely basophilic erythrocyte, erythrocyte). A consensus scheme was used to obtain the "true" classification of the cells. Cell types were characterized by three methods: absorbance spectra, dye binding, and chromaticities. Within both cell lines nuclear maturation is accompanied by an overall increase in peak absorbance with little shift in the position of the maximum. Generally, binding of azure B and eosin increases; azure B dimer/monomer ratios show a slight downward trend during maturation. Changes in chromaticities are to bluish purples of increasing saturation. Cytoplasmic changes accompanying maturation are much more striking than nuclear changes, and again the two cell lines show similarities. Generally, there is decreased binding of azure B during maturation. In the erythroid line, the Soret band of hemoglobin becomes increasingly prominent. Chromaticities change from bluish purples to purplish pinks, particularly in the erythroid line.

Azure Stains↗
PubMed1984

Studies on Papanicolaou staining. III. Quantitative investigations of orangeophilia and cyanophilia.

This paper provides data derived from the visible light absorbance spectra of Papanicolaou stained epithelial cells from the uterine cervix. Twenty-four types of spectra have been considered, namely, those derived from orangeophilic and cyanophilic nuclei and cytoplasms of superficial, intermediate, parabasal and dysplastic cells, and cells of carcinoma in situ and invasive carcinoma. Wavelengths of maximum absorbance and peak absorbances are tabulated. The proportions of bound orange G, eosin Y, aluminum-hematein and light green SF yellowish have been calculated. For the majority of cell types, dyebinding differences between orangeophilic and corresponding cyanophilic substrates were statistically significant. CIE coordinates were calculated from absorbance spectra; again differences between organeophilic and cyanophilic cells were statistically significant in most cases. Although the designation of cells as orangeophilic or cyanophilic is made on the basis of cytoplasmic coloration, the nucleus is also usually orangeophilic or cyanophilic. These nuclear differences are real and not due to the effects of over- and underlying cytoplasm.

Cell Nucleus↗
PubMed1984

Colorimetry for the stain technologist. I. The specification of color.

This paper describes color specification for the stain technologist. The principles of color stimulus specification are reviewed in terms of the conventions of the Commission Internationale de l'Eclairage (CIE). The text is largely self-contained and has been written so that it can be understood easily by a reader with no prior knowledge of color science. The paper starts with definitions of color and related psychological, psychophysical and colorimetric terms. X, Y, Z color space is described. It is shown that any color stimulus may be unambiguously defined in terms of a set of three numbers. The CIE 1931 Chromaticity Diagram is described. Worked examples are given for the calculation of tristimulus values and chromaticity coordinates using three different illuminants. The usefulness of color specification is illustrated by a number of examples using Romanowsky stained blood cells or Papanicolaou stained epithelial cells from the uterine cervix.

Blood Cells↗
PubMed1984

Colorimetry for the stain technologist. II. The specification of chromaticity difference.

This paper describes the calculation of chromaticity difference. The text has been written specifically for the stain technologist and is largely self-contained. The concept of a uniform chromaticity scale (UCS) is described. A UCS is a diagram in which equal perceived differences in chromaticity are represented by equal distances anywhere on the diagram. UCSs are developed by transformations of the CIE 1931 chromaticity diagram, and may be linear (projective) or nonlinear. The effectiveness of the various transformations has been assessed using published data on discrimination of chromaticity. The usefulness of chromaticity difference calculations is illustrated by histological examples, including Romanowsky stained blood cells and Papanicolaou stained cells from the uterine cervix. Six UCSs are used in these examples, two projective and four nonlinear.

Animals↗
PubMed1984

Colorimetry for the stain technologist. III. The specification of color difference.

This paper illustrates the calculation of color differences, involving luminance as well as chromaticity components. Color differences have been calculated for a large number of stained histological objects. Four different color difference formulae have been used, namely, those associated with the FMC 2, U*V*W*, L*u*v* and L*a*b* systems. Comparison has first been made between various hematological substrates after staining with two different azure B-eosin Y stains. Next, comparison is made for the same substrates after staining with one of the azure B stains and a methylene blue-eosin Y stain. Pairwise comparison is also made of various substrates from the epithelium of the uterine cervix after Papanicolaou staining. Finally, pairwise comparison documents color differences accompanying maturation for the erythroid and myeloid cell lines in azure B-eosin Y stained bone marrow. The limitations of current color difference formulae are discussed.

Blood Platelets↗
PubMed1984

Malignant cell detection and cervical cancer screening.

A study was conducted to determine the isolated, single-cell detection characteristics of human observers as this information relates to cervical cancer screening. Two interrelated experiments were performed. First, the receiver operating characteristic (ROC) was obtained for slide screening. In this experiment, approximately 1,200 slides were examined. Second, ROCs were obtained for human observer cell discrimination, using a rating method. An individual's curves were computed, assuming a multiple decision criterion. In this experiment, 6,375 cells from the same specimens used in the slide screening experiment were studied. In both experiments, results were analyzed using a Gaussian signal-detection model. This approach provided analytical detection criteria and rigorous definition of ROCs. These experiments addressed the problem of where the screening information lies: (1) in individual cells alone or (2) with additional components in global or other a priori information. We quantified the detection requirements of (1) the Papanicolaou smear screening process, Az = 0.99, and (2) the capabilities of trained cytotechnologists on isolated single cells, Az = 0.87. System modeling using intermediate cell detection instead of "rare event" detection resulted in a reduction of the predicted number of cells required for analysis from approximately 60,000 to 750.

Female↗
PubMed1981

Microspectrophotometric studies of Romanowsky stained blood cells. II. Comparison of the performance of two standardized stains.

This paper describes a comparison of the performance of two standardized Romanowsky blood stains, namely those of Marshall et al. and Wittekind et al., both containing azure B and eosin alone. Stain performance is assessed objectively by the use of three complementary techniques, all based on the visible absorbance spectra of stained cellular substrates. The first of these techniques is a simple comparison of the shapes and heights of the absorbance spectra. The second technique uses the CIE Colorimetric System, and thus permits the quantitation of colour in a manner that agrees with human observation. CIE co-ordinates (chromaticity points, luminance) are calculated directly from absorbance spectra. The third technique is that of spectral subtraction, which yields a set of factors which describe the quantities of component dyes which are bound by the object. This technique, unlike the other two, requires a priori knowledge of the dyes used in the stains, and their spectra when bound to cellular substrates. Although the differences between the two methods are subtle, and hard for the subjective observer to define, the objective methods described here do show statistically significant differences. Wittekind's stain produces less intense staining, except for lymphocyte and monocyte cytoplasms. To the human eye, the differential coloration of these two substrates is more pronounced, but the difference between all nuclei and cytoplasm is less marked. The major difference in the uptake of dye components is in the small quantities of eosin dimer that are bound in this technique.

Blood Cells↗
PubMed1980

Microspectrophotometric studies of Romanowsky stained blood cells. I. Subtraction analysis of a standardized procedure.

This paper describes a microspectrophotometric study of blood smears stained by a simple, standardized Romanowsky technique, using only the dyes azure B and cosin. Absorbance spectra are presented for twenty-two classes of cellular object, and for the two dyes in solution, together with tabulations of spectral maxima, and suitable wavelengths for use in automated image processing. The colours of objects stained with azure B/eosin are discussed in terms of absorbance spectra. By a spectral subtraction technique, it is shown that the differential colouration of various cell structures may be explained satisfactorily in terms of the varying proportions of only four dye components. These are the monomers and dimers of azure B and eosin. Polymerization was found to occur both in solution and on binding to biopolymers. A similar analysis of a conventional Romanowsky stain would present much greater difficulties, due to the greater number of dye components, which, however, contribute little to the colours observed.

Azure Stains↗