Micromachining of a piezocomposite transducer using a copper vapor laser

A 1-3 piezocomposite transducer with front face dimensions of 2 x 2 mm has been micromachined using a copper vapor laser. The device consists of PZT5A piezoceramic pillars with a 65-micron pitch suspended in a low viscosity thermosetting polymer. The kerf width is 13 microns, and the transducer thickness is 170 microns, making the device suitable for ultrasonic reception at frequencies close to 10 MHz.

Extremophilic orgainisms as and unexplored source fo antifungal compounds

Extracts of the biomasses and fermentation broths of 217 extremophilic microorganisms isolated from a number of locales were screened for antifungal activity using whole-cell and mechanism-based in vitro assays. Importantly, eleven broth extracts had activity against several Candida species and Aspergillus fumigatus in whole-cell in vitro assays. One broth specifically inhibited (1,3)beta-glucan synthase activity and four specifically inhibited ketol-isomerase activity, suggesting a mode of action of the antifungal compound(s) present in these extracts. The extract from one thermophile, a novel species of Pseudomonas, was fractionated, an active compound purified and its structure determined. The compound was identified as pyochelin, a previously identified iron-binding compound with heretofore undescribed antifungal activity. To our knowledge, this is the first report demonstrating that extremophiles synthesize compounds that have antifungal activity.

The radiation field characteristics of piezoelectric polymer membrane transducers when operating into air

This paper describes the evaluation of the radiation field characteristics of PVDF membrane transducers, whereby the active area is defined by an appropriate electrode pattern when operating into air. Measurement, including conventional scanning of the fields and laser vibrometry, is supplemented by finite element modeling over the frequency range 500 kHz to 1.1 MHz. Contrary to expectation, the surface displacements are nonuniform, giving rise to premature axial focusing of the field. This is shown to be caused by generation of the zero order symmetrical Lamb wave, arising from the electric field discontinuity at the electrode boundary of the transducer.

Activation of rat macrophages by Betafectin PGG-glucan requires cross-linking of membrane receptors distinct from complement receptor three (CR3)

PGG-glucan (Betafectin) is a soluble, highly purified yeast (1,3)-beta-glucan with broad anti-infective and immunomodulatory activities. These studies evaluated the ability of PGG-glucan to directly elicit O2- and tumor necrosis factor alpha (TNF-alpha) production by rat leukocytes in vitro. Particulate beta-glucan stimulated O2- production by the rat NR8383 alveolar macrophage cell line and resident rat peritoneal macrophages, but soluble PGG-glucan did not. In contrast, presentation of PGG-glucan to cells after covalent immobilization to a plastic surface caused a direct stimulation of O2- and TNF-alpha production. The O2- response of rat leukocytes to immobilized PGG-glucan was inhibited by soluble PGG-glucan, indicating that cellular responses to both immobilized and soluble PGG-glucan occur via common cell surface receptors. Because complement receptor type three (CR3) has been proposed as a beta-glucan receptor on human leukocytes, NR8383 cells were evaluated for the presence of CR3. Indirect immunofluorescence and flow cytometric analysis showed that despite being responsive to both particulate and immobilized beta-glucans, NR8383 cells expressed no detectable CR3. These results indicate that the beta-glucan receptors on NR8383 cells are not CR3 and suggest that physical presentation plays an important role in inducing pro-inflammatory leukocyte responses to PGG-glucan.

Development of a PVDF membrane hydrophone for use in air-coupled ultrasonic transducer calibration

This work describes the use of a polyvinylidene fluoride (PVDF) membrane hydrophone for application in air-coupled transducer calibration. A one-dimensional theoretical analysis is used to demonstrate the potential and performance of PVDF as a hydrophone material over the frequency range 100 kHz to 5 MHz included in the evaluation is the influence of deposited metallic electrode layers on the sensitivity of the material. Experimental validation over the restricted range 400 kHz to 1 MHz is provided by a coplanar 0.028 mm thick membrane hydrophone in conjunction with a custom built 1-3 piezocomposite transmitter. Calibration of the membrane hydrophone is performed by employing a standard hydrophone that has been calibrated to a primary standard in a water medium. Justification for such an approach is presented within the theoretical analysis which provides a close correlation with experimental data. The generation of Lamb waves at critical angles in the PVDF and their subsequent influence on the directional response of membrane hydrophones operating in air is also addressed. A method for partial suppression of the Lamb waves, based around perforation of the membrane (either in whole or in part), is evaluated experimentally with reasonable results.

Interleukin-1 receptor antagonist inhibits proteoglycan breakdown in antigen induced but not polycation induced arthritis in the rabbit

OBJECTIVE

To compare the alterations in proteoglycan metabolism in antigen induced arthritis and polycation induced arthritis and to determine the involvement of interleukin-1 (IL-1) in the cartilage degradation that occurs in these models of rheumatoid arthritis (RA).

METHODS

The time course for loss of proteoglycan into the synovial fluid (SF) and inhibition of proteoglycan synthesis, as well as depletion of articular cartilage proteoglycan content, was compared in rabbit antigen arthritis and polycation arthritis. The ability of recombinant IL-1 receptor antagonist IL-1ra to block the acute cartilage loss at 24 h in these models was investigated, compared to its ability to block the cartilage breakdown induced by direct administration of IL-1 in rabbits.

RESULTS

Initial loss of cartilage proteoglycan was accompanied by release of high levels of glycosaminoglycan (GAG) into the SF and decrease in proteoglycan synthetic rates in both antigen and polycation induced arthritis SF GAG rapidly returned to control levels, while proteoglycan synthesis and cartilage proteoglycan content remained depressed, suggesting that the inhibition in proteoglycan synthesis prevented recovery to normal levels. GAG loss from the cartilage into the SF in response to IL-1 injection, as well as other effects of IL-1 challenge, was blocked in a dose dependent manner by IL-1ra administered either intraarticularly (ED50 = 160 ng) or intravenously (iv) (ED50 = 0.09mg/kg). In the antigen induced arthritis model, IL-1ra (20 mg/kg, iv -2h) inhibited GAG release by 40%, whereas in polycation induced arthritis no inhibition was observed even with repeated administration of high doses of inhibitor.

CONCLUSION

These studies suggest that sustained depression of proteoglycan synthesis may be responsible for the chronic depletion of articular cartilage proteoglycan in the antigen and the polycation model of RA. However, while IL-1 may play a role in the initial breakdown of articular cartilage in antigen induced arthritis, it does not appear to be involved in polycation induced arthritis in the rabbit.

Pharmacokinetics of antisense oligonucleotides

Antisense oligonucleotides are promising therapeutic agents for the treatment of life-threatening diseases. Intravenous injection of phosphodiester oligonucleotide analogue (P-oligonucleotide) in monkeys shows that the oligonucleotide is degraded rapidly in the plasma with a half-life of about 5 minutes. Administration of a single dose of the phosphorothioate (S-oligonucleotide) in animals by the intravenous route reveals biphasic plasma elimination. An initial short half-life (0.53 to 0.83 hours) represents distribution out of the plasma compartment and a second long half-life (35 to 50 hours) represents elimination from the body. This elimination half-life was similar when the oligonucleotide was administered subcutaneously. In contrast, methylphosphonate oligonucleotides have an elimination half-life of 17 minutes in mice. S-Oligonucleotide was distributed into most of organs of rats and mice. Liver and kidney were the 2 organs with highest uptake of the oligonucleotide. The S-oligonucleotide was primarily excreted in urine. Up to 30% was excreted in the first 24 hours. Repeated daily intravenous injections of a 25-mer S-oligonucleotide into rats showed that the concentrations in the plasma are at steady-state during the 8 days' administration. The data represented here support the potential utility of phosphorothioate and methylphosphonate oligonucleotides as therapeutic agents in vivo.

Antiinflammatory 4,5-diarylpyrroles: synthesis and QSAR

A series of 2-substituted- and 2,3-disubstituted-4-(4-fluorophenyl)-5-[4-(methylsulfonyl)phenyl]-1H- pyrroles was synthesized and found to be active in the rat adjuvant arthritis model of inflammation. The most active compounds were the 2-halo derivatives in the order of chloro > bromo > iodo. The same pattern of activity was observed for the 2,3-dihalopyrroles. Quantitative structure-activity relationship studies suggested that the activity could be correlated with the molar refractivity and the inductive field effect of the 2-substituent and the lipophilicity of the 3-substituent.

Remapping disparate images for coincidence

With the development of complex multimode computerized microscope systems, it is possible and necessary to obtain images of the same area of the microscopical preparation by several methods of microscopy, such as differential interference contrast, reflection interference microscopy, several wavelengths of fluorescence microscopy, laser scanning and confocal modes. Thus, varied information may be obtained about a single field, in the form of a set of images, taken at different ports of the microscope, using different digitizing cameras, each appropriate to certain tasks. For comparative purposes, the images should be superimposable, pixel by pixel, but in general they are not--they differ in image shape and size, magnification, distortion, centration and orientation. This paper shows how the problem may be approached, using an extension of the remapping procedures described in a previous paper, in which images of a separate grid reference slide are used to detect, quantify and correct the image errors. Affine remapping, without the use of grid images, is also described.

A novel fluorescence ratiometric method confirms the low solvent viscosity of the cytoplasm

Two homologous indocyanine dyes, Cy3.18 and Cy5.18, can be used as a ratio pair for fluorometric determination of solvent viscosity. Succinimidyl ester derivatives of these dyes can be attached to inert carrier macromolecules, such as Ficoll 70, for measurement of intracellular or intravesicular solvent viscosity. When the viscosity of the solvent was varied by various methods, the fluorescence intensity ratio (Cy3/Cy5) in a mixture of Cy3.18-Ficoll 70 (Cy3F70) and Cy5.18-Ficoll 70 (Cy5F70) in solution was found to be solely a function of solvent viscosity and was insensitive to other solvent parameters such as dielectric constant, temperature, and the ability of the solvent to form hydrogen bonds. Most important, it was insensitive to the presence of large macromolecules, such as proteins, which increase the shear viscosity but have little effect on solvent viscosity. Following microinjection into the cytoplasm of living tissue culture cells, no binding of Cy3F70 or Cy5F70 to intracellular components was detected by fluorescence recovery after photobleaching. Fluorescence intensity ratio imaging of Cy3F70 and Cy5F70 in non-motile interphase CV1 and PtK1 cells showed that the solvent viscosity of cytoplasm was not significantly different from water and showed no spatial variation.

Interleukin-1 differentially modulates chondrocyte expression of cyclooxygenase-2 and phospholipase A2

Interleukin-1 beta (IL-1) increases the synthesis of prostaglandins as well as the expression of synovial fluid phospholipase A2 (PLA2) mRNA and activity by chondrocytes. In order to examine the potential involvement of cyclooxygenase in the induction of prostaglandins by IL-1, the effect of IL-1 on rabbit articular chondrocyte expression of cyclooxygenase enzymes was investigated. By Northern analyses, mRNA for cyclooxygenase-2 (COX-2) was found to be constitutively expressed, and its expression was increased in cultures treated for 24 h with IL-1 (100 ng/ml). Cyclooxygenase-1 mRNA was not detected in control or IL-1-treated cultures. IL-1 caused a concentration-dependent increase in steady-state levels of COX-2 message as assessed by slot-blot analyses. Half-maximal induction of the COX-2 message levels was estimated to require 1.2 ng/ml IL-1. In duplicate slot blots probed with a cDNA for synovial fluid PLA2, half-maximal induction of PLA2 mRNA was estimated to require 0.15 ng/ml IL-1, approximately 10-fold less IL-1 than required for COX-2. In addition, maximal increase in COX-2 message levels was only 3-fold as compared with a 13-fold induction of PLA2. No change in message levels for the intracellular protein, actin, was found between control and experimental cultures. Cycloheximide enhanced COX-2 transcript levels, but did not modulate IL-1 induction of COX-2. Actinomycin D did not inhibit IL-1 augmentation of COX-2 mRNA levels; whereas, induction of PLA2 mRNA levels was completely inhibited, implicating transcriptional mechanisms in the induction of PLA2 but not COX-2 mRNA. These data demonstrate that chondrocyte expression of COX-2 and synovial fluid PLA2 are differentially modulated by IL-1.

Effects of IL-1 muteins on cartilage degradation and as inducers of acute inflammation

IL-1 peptides with N-terminal amino acid mutations were cloned and expressed to help characterize structural requirements for activity. Addition of Thr-Asn to the N-terminus (DP516) or substitution of the first two residues (Ala-Pro) of mature, native IL-1 beta with Thr-Met (DuP118) had no effect on the potency of the muteins in stimulating proteoglycan breakdown and inhibiting proteoglycan synthesis in vitro, or inducing mouse paw swelling in vivo. When Arg in position 4 of DuP118 was replaced by Glu (Glu-4), proteoglycan-synthesis-inhibitory activity was reduced to 20% and proteoglycan-degrading activity to 2% of that induced by native IL-1 beta. Glu-4 was much less active in inducing mouse paw swelling and gave maximal swelling about 40% that of native IL-1 beta. The data suggest that the presence of the positively charged side chain of Arg in position 4 may be important for the activity of IL-1 and may be useful in designing specific IL-1 receptor agonists/antagonists.

Imaging cytometry by multiparameter fluorescence

A system is described for performing multicolor fluorescence image cytometry of cell preparations. After the setting up stage, the operation is automatic: the microscope fields are found and focused; then images are acquired for each fluorophore, corrected and analyzed, without any operator interaction. Human peripheral blood lymphocytes on microscope slides were used as a test system. In these experiments, three fluorescent antibodies were used to identify lymphocyte sub-populations, and a DNA content probe was used to identify all nucleated cells. The cell subset percentages determined by image cytometry were comparable to percentages obtained when cells from the same preparation were analyzed by flow cytometry. Multicolor fluorescence imaging cytometry can potentially be extended to the analysis of cells in smears, fine needle biopsies, imprints, and tissue sections.

In vivo inhibition of tumor growth of B16 melanoma by recombinant interleukin 1 beta. II. Mechanism of inhibition: the role of polymorphonuclear leukocytes

Recombinant human interleukin 1 beta (IL 1 beta) inhibits growth of B16 melanoma in syngeneic C57BL/6 mice in a dose-dependent manner when given intratumorally, intradermally, or intramuscularly over a period of 5 to 7 days. Inhibition of tumor growth was rapid and measurable within 3 days after the initial injection and occurred regardless of the route of injection. However, only intratumoral (ITU) injections of IL 1 beta resulted in greater than 90% inhibition in tumor growth. This enhanced inhibition of tumor growth was not dependent on T or NK cells since inhibition of tumor growth occurred in nude and Beige mice. Also, a profound lymphopenia occurred in mice receiving IL 1 beta. Inhibition of tumor growth did correlate with an increase in the number of polymorphonuclear leukocytes (PMN's) in the circulation. However, only ITU injections of IL 1 beta increased the number of PMN's within the tumors. IM injections of IL 1 beta, while increasing the number of PMN's in the circulation, did not increase the influx of PMN's into the tumors. Furthermore, the transfer of PMN's directly into B16 tumors caused a 49% reduction in tumor growth without the presence of IL 1 beta. These results suggest that in vivo, PMN's may effectively control the growth of tumors and that IL 1 beta may increase this effectiveness by increasing the number of PMN's in the circulation and by locally stimulating the production of chemotactic factors for PMN's within the tumor.

Anti-inflammatory and safety profile of DuP 697, a novel orally effective prostaglandin synthesis inhibitor

DuP 697 (5-bromo-2[4-fluorophenyl]-3-[4-methylsulfonylphenyl]-thiophene) is a potent inhibitor of paw swelling in nonestablished and established adjuvant arthritis in rats (ED50 = 0.03 and 0.18 mg/kg/day, respectively). DuP 697 had no effect on phenylquinone writhing in rats (ED50 greater than 100 mg/kg), but was analgetic against inflammation-related pain in the Randall-Selitto assay (ED30 = 3.5 mg/kg) and was a very potent antipyretic agent (ED50 = 0.05 mg/kg). The drug was not ulcerogenic in rats at single doses up to 400 mg/kg. DuP 697 (5 mg/kg i.v.) did not alter renal blood flow or the renal vascular response to angiotensin II in furosemide-pretreated, volume-depleted rats. In contrast, indomethacin (5 mg/kg i.v.) decreased renal blood flow and potentiated the renal vascular response to angiotensin II in these animals. DuP 697 was a moderate inhibitor of bull seminal vesicle prostaglandin (PG) synthesis (IC50 = 2.4 X 10(-5) M) and a potent inhibitor of rat brain PG synthesis (IC50 = 4.5 X 10(-6) M) but was ineffective against rat kidney PG synthesis (IC50 7.5 X 10(-5) M). These differential effects of DuP 697 on PG synthesis by various tissues may account for its high potency as an anti-inflammatory and antipyretic agent and its minimal toxicity profile.

2-substituted-1-naphthols as potent 5-lipoxygenase inhibitors with topical antiinflammatory activity

The synthesis, biological evaluation, and structure-activity relationships of a series of 1-naphthols bearing carbon substituents at the 2-position are described. These compounds are potent inhibitors of the 5-lipoxygenase from RBL-1 cells and also inhibit bovine seminal vesicle cyclooxygenase. Structure-activity relationships for these two enzymes are different, implying specific enzyme inhibition rather than a nonspecific antioxidant effect. 2-(Aryl-methyl)-1-naphthols are among the most potent 5-lipoxygenase inhibitors reported (IC50 values generally 0.01-0.2 microM) and show excellent antiinflammatory potency in the mouse arachidonic acid ear edema model. To study the effects of structure on in vitro and in vivo activity, four general features of the molecules were varied: the 2-substituent, the 1-hydroxyl group, substitution on the naphthalene rings, and the 1,2-disubstituted naphthalene unit itself. 2-Benzyl-1-naphthol (5a, DuP 654) shows a very attractive profile of topical antiinflammatory activity and is currently in clinical trials as a topically applied antipsoriatic agent.

Interleukin-1 beta stimulates phospholipase A2 mRNA synthesis in rabbit articular chondrocytes

A cDNA that codes for human rheumatoid synovial fluid phospholipase A2 (PLA2) hybridized with a RNA of the same size (900 base pairs) isolated from rabbit articular chondrocytes (RAC). Treatment of RAC with 100 ng/ml recombinant human interleukin-1 beta (IL-1) for 24 hours caused a 13-fold increase in mRNA for this PLA2. Timecourse studies demonstrated that maximal induction of PLA2 mRNA occurred by 16 hours post addition of IL-1 (100 ng/ml). Augmentation of RAC PLA2 mRNA levels was dose-dependent; half-maximal induction was estimated to require 0.15 ng/ml IL-1. Actinomycin D inhibited IL-1 effects on PLA2 mRNA levels. Coordinate effects of IL-1 on RAC PLA2 activity were observed with respect to time and dose dependence as well as actinomycin D sensitivity.

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.

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.

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.

Multiple spectral parameter imaging in quantitative fluorescence microscopy. I: Quantitation of bead standards

Digitized images from fluorescence microscopy may suffer from nonlinearity of camera response to illumination intensity, from uneven spatial response of the camera, and from uneven illumination of the microscopical field. Structureless fluorescence standard slides are used to characterize the camera response. This information permits the images to be corrected for all the above errors, in one operation. The computer algorithms are described, and also those for thresholding and finding objects. The method is illustrated by tests using fluorescent beads.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

The energy distribution about the image of a point

A mathematical formulation is presented of the three dimensional distribution of intensity in the image of a bright point. Other equivalent formulations have been described before, but this one appears to have certain practical advantages. The formulation has been used in computer programs to provide tomograms and isophote contour maps of the intensity distribution. A following paper will describe the application of the formulation to differential interference contrast-microscopy.