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Value of patch testing in atopic dermatitis.

BACKGROUND: Because patients with atopic dermatitis are less prone to type IV allergies, there has been controversy regarding the role of patch testing in these patients. OBJECTIVE: The present study was conducted to evaluate the role of patch testing in atopic individuals. METHODS: One-hundred patients with hand eczema were patch tested using the standard patch test battery (HERMAL, Kurt Herrmann, Reinbek, West Germany) and the Finn chamber units. The total immunoglobulin class E (IgE) level was determined and correlated to the results of patch testing. RESULTS: Eighty-seven patients had positive patch test reactions. Among the 87 patients, 39 (44.8%) had atopic dermatitis. The most common allergens yielding positive results were nickel sulfate, 2.5%, (58.6%); potassium dichromate, 0.25% (56.3%); carba mix, 3%, (44.82%); formaldehyde, 1% in H2O, (40.22%); neomycin sulfate, 20%, (33.3%); and balsam of Peru 25%, (17.24%) respectively. Patients with atopic dermatitis were more frequently sensitive to neomycin sulfate than nonatopics. CONCLUSION: Patients with atopic dermatitis should be patch tested when indicated because they also develop contact allergic sensitization to a significant degree. Our observations indicate that patch testing with standard allergens often adds valuable information about contact sensitivity in these patients.

Adult↗

Contact sensitization to sunscreens.

BACKGROUND: Para aminobenzoic acid (PABA) derivatives and cinnamate are chemical sunscreens that protect against UVB (290 to 320 nm). They may occasionally produce contact and photocontact sensitization. OBJECTIVE: To report a sensitization to octyl-dimethyl-PABA and photosensitization to 2-ethylhexyl-p-metossicinnamate in a 31-year-old man. METHODS: A patient with a 3-year history of a relapsing dermatitis involving the face, neck, legs, and knees is reported. The eruption had recurred every summer after sunlight exposure. Patch tests with International Contact Dermatitis Research Group (IC-DRG) standard series and the photopatch series (Hermal-Trolab, Reinbek, Germany) using Finn chambers on Scanpor (Norgesplaster A/S, Oslo, Norway) were carried out. RESULTS: We found a positive reaction to Balsam of Peru, fragrance mix, Escalol 507, and Parsol MCX (Hermal-Trolab, Reinbek, Germany). Photopatch test revealed a positive reaction only for Parsol MCX. CONCLUSION: The incidence of allergic contact dermatitis to sunscreens is considered low. Recently sunscreens patch test concentrations have been increased from 2% to 10%. These higher percentages will probably permit the identification of more cases of sunscreens allergy in the near future.

4-Aminobenzoic Acid↗

Factors defining sensitive skin and its treatment.

BACKGROUND: Users of cosmetics and skin care products often report adverse reactions ranging from itching and dryness to intense inflammatory responses such as erythema or wheal and rash. Self-assessment is not always an accurate parameter for categorizing skin as sensitive or nonsensitive, although it can be valuable. For this reason, it is important to define sensitive skin by more objective factors. OBJECTIVE: Studies were undertaken to determine if objective biophysical measurements could detect differences in barrier function between those individuals who identified themselves as having sensitive skin and those self-identified as having normal skin. In addition, the effects of treatment on barrier functions of individuals with sensitive skin were determined. METHODS: Three main factors that contribute to cutaneous reactivities were observed for the estimation of skin sensitivity: barrier functions, reactivity to irritants, and neuronal responses manifested as sensory reactions. Barrier functions of the skin was tested by gentle removal of the stratum corneum with simple cellophane tape stripping followed by measurement of transepidermal water loss (TEWL) as a marker of barrier loss. The onset and intensity of skin reaction against an irritant, balsam of Peru, was tested on the same individuals to observe the reactivity of their skin. Using the lactic acid sting test, additional information regarding skin sensitivities was obtained. RESULTS: Sensitive skin individuals exhibiting easy barrier damage possess delicate skin that is also highly reactive to irritants. When these individuals used a regimen of products that contained minimal preservatives and no surfactants for 8 weeks, the skin barrier and reactivity changed such that it was similar to nonsensitive skin. CONCLUSIONS: Skin sensitivity is observed because of a combination of factors, including a disrupted barrier and a tendency to hyperreact to topical agents. Treatment with special topical skin care formulations can reduce overall skin sensitivity.

Adult↗

Dioxopromethazine-induced photoallergic contact dermatitis followed by persistent light reaction.

BACKGROUND: Although photosensitivity after photoallergy to topical phenothiazine antihistamines is well known, there have been no previous reports of dioxopromethazine inducing this phenomenon. OBJECTIVE: A housewife used 0.5% dioxopromethazine in Prothanon gel for palpebral pruritus and developed severe dermatitis of the lower eyelids with spread to the sun-exposed areas. METHODS: The minimal erythema doses and the minimal infiltrate doses for ultraviolet A (UVA) and ultraviolet B (UVB) were established before photopatch testing and at intervals up to 497 days thereafter. Test sites were read up to 144 hours after irradiation. Photopatch testing was performed with Prothanon gel, dioxopromethazine hydrochloride 0.001% to 0.5%, and the standard photopatch test tray (Hermal/Trolab). For patch testing, various series of the German Contact Dermatitis Group were applied. RESULTS: Minimal erythema doses for UVA were diminished before photopatch testing and at intervals up to 500 days after Prothanon gel was discontinued. Exposure to UVB provoked abnormal delayed infiltrated reactions. Clinically the photosensitivity persisted within this period. Photoallergic reactions were seen with Prothanon gel, dioxopromethazine hydrochloride 0.005% to 1.0%, and promethazine hydrochloride 0.1%. The patient gave positive patch test reactions to various fragrance materials, balsam of Peru, costus oil, and propylene glycol. CONCLUSION: Because topical dioxopromethazine may cause photoallergic contact dermatitis followed by long-lasting photosensitivity even after contact has been discontinued, its withdrawal from the market is recommended.

Antipruritics↗

Contact sensitivity in patients with leg ulcerations: a North American study.

OBJECTIVES: (1) To determine the prevalence of allergen sensitivity in patients with past or present leg ulcers in 2 North American study centers vs European study findings and the North American Contact Dermatitis Group (NACDG) database and (2) to delineate a standard battery of allergens for patch testing in North American patients that is representative of the newer dressings and wound care products. DESIGN: Fifty-four patients, with or without dermatitis, were prospectively entered in the study. The patients were patch tested to the NACDG standard series and a comprehensive supplemental series of 52 allergens. SETTING: Wound healing clinics at Boston University Roger Williams Medical Center and University of Ottawa. RESULTS: Sixty-three percent (n = 34) of patients had 1 or multiple positive patch test results, and 37% (n = 20) had no positive patch test result. The most common allergens were Myroxylon pereirae (balsam of Peru) (30% [16/54]), bacitracin (24% [13/54]), fragrance mix (20% [11/54]), wood tar mix (20% [11/54]), propylene glycol (14% [7/52]), neomycin sulfate (13% [7/54]), benzalkonium chloride (13% [7/54]), carba mix (11% [6/54]), nickel sulfate (11% [6/54]), and control gel hydrocolloid (11% [6/54]). CONCLUSIONS: Comparable to European study findings, there is a high incidence of positive patch test results in patients with past or present leg ulcerations. The incidences of the most common allergens in our patient population were higher than those seen in the NACDG, except for nickel. Using a modified leg ulcer series along with the standard NACDG series is important in evaluating patients with leg ulcers.

Aged↗

Insect-plant interactions: endocrine defences.

It is the inevitable consequence of evolution that competitive species living together in a restricted space must try to exclude each other. Plants and insects are prime examples of this eternal competition, and although neither of these is in danger of extinction, their mutual defensive strategies are of compelling interest to the human race. Plant defences based on the insecticidal activity of certain of their secondary chemicals are readily apparent. Only through research into the fundamentals of insect physiology and biochemistry are more subtle defensive mechanisms revealed, linked to the disruption of the insect endocrine system. A diverse number of chemical structures are found in plants, which interfere with hormone-mediated processes in insects. Examples include: mimics of the insect's juvenile hormones such as juvabione from the balsam fir and the juvocimenes from sweet basil, which lethally disrupt insect development, and the precocenes found in Ageratum species, which act as anti-juvenile hormonal agents. The latter appear to serve as 'suicide substrates', undergoing activation into cytotoxins when acted on by specialized enzymes resident in the insect endocrine gland (corpus allatum) that is responsible for juvenile hormone biosynthesis and secretion. Consideration of these plant defensive strategies, which have been reached through aeons of evolutionary experimentation, may assist the human race in its defences against its principal competitors for food, fibre and health.

Adaptation, Biological↗

Chiral MEKC-LIF of amino acids in foods: analysis of vinegars.

The formation of D-amino acids (D-aa's) in many fermented foods depends, among other factors, on the particular fermentation conditions, the action and autolysis of the microorganisms involved. In this sense, the analysis of chiral amino acids is an interesting analytical strategy for food scientists, since these compounds can be used as bacterial markers and can help, e.g., to detect adulterations, microbiological contaminations, etc. In this work, a fast and sensitive method based on MEKC-LIF has been developed to analyze and quantitate L-amino acid (L-aa) and D-aa in vinegars. The chiral MEKC-LIF procedure uses 100 mM sodium tetraborate, 30 mM SDS, and 20 mM beta-CD at pH 9.7 as running buffer, obtaining a good separation of the main vinegar L-/D-aa previously derivatized with fluorescein isothiocianate. Namely, L/D proline, alanine, arginine, glutamic, and aspartic acid, plus the nonchiral amino acid gamma-aminobutyric acid are separated in less than 20 min with high efficiency (up to 720,000 plates/m) and good sensitivity (LODs lower than 16.6 nM were achieved). Several D-aa's were detected and quantified in balsamic, sherry, white wine, and cider vinegars using this MEKC-LIF procedure, observing interesting differences in their L-aa and D-aa profiles and contents.

Acetic Acid↗

Fate of spinosad in litter and soils of a white spruce plantation in central Ontario.

Spinosad is a natural insecticide with potential as a novel biorational control agent for spruce budworm (Choristoneura fumiferana [Clem]), the most destructive insect defoliator of spruce and balsam fir in Canada. Concurrent terrestrial fate experiments were conducted under full coniferous canopy and in a natural opening of a mature white spruce (Piecea glauca [Moench]) plantation of central Ontario to examine the fate and persistence of spinosad in the forest floor and underlying soils. Mean initial residues of spinosyn A and D were approximately 0.2 and 0.02 microgram g-1, respectively, in thatch and exposed soils, but were substantially higher, 2.72 and 0.36 micrograms g-1, in litter under coniferous canopy. Results demonstrated that spinosad residues in spruce litter, graminaceous thatch and exposed sandy loam soils dissipated rapidly, following hyperbolic or exponential decline models. Dissipation time (DT50) values ranged from 2.0 to 7.8 days, depending on matrix and experimental conditions. Transient increases in demethylated metabolite residues confirmed that the parent product was degraded in situ. No evidence of vertical mobility of any of the analytes was observed.

Anti-Bacterial Agents↗

Composition and antibacterial activity of Abies balsamea essential oil.

The antibacterial activity of the essential oil of Abies balsamea (balsam fir) was evaluated against Escherichia coli and Staphylococcus aureus. The essential oil of A. balsamea was found to be inactive against E. coli (>100 microg/mL) and active against S. aureus, with an MIC of 56 microg/mL. The oil composition was analysed by GC-MS and the antibacterial activity of each oil constituent was determined. The essential oil of A. balsamea is essentially constituted of monoterpenes (>96%) and some sesquiterpenes. beta-pinene (29.9%), delta-3-carene (19.6%) and alpha-pinene (14.6%) were the major components. beta-pinene and delta-3-carene were found inactive against both bacteria strains. However, three constituents of the essential oil were active against S. aureus: alpha-pinene, beta-caryophyllene (0.4%) and alpha-humulene (0.2%) with MIC values of 13.6 microg/mL, 5.1 microg/mL and 2.6 microg/mL, respectively.

Abies↗

Environmental hazards of aluminum to plants, invertebrates, fish, and wildlife.

Aluminum is extremely common throughout the world and is innocuous under circumneutral or alkaline conditions. However, in acidic environments, it can be a major limiting factor to many plants and aquatic organisms. The greatest concern for toxicity in North America occurs in areas that are affected by wet and dry acid deposition, such as eastern Canada and the northeastern U.S. Acid mine drainage, logging, and water treatment plant effluents containing alum can be other major sources of Al. In solution, the metal can combine with several different agents to affect toxicity. In general, Al hydroxides and monomeric Al are the most toxic forms. Dissolved organic carbons, F, PO(3)3- and SO(4)2- ameliorate toxicity by reducing bioavailability. Elevated metal levels in water and soil can cause serious problems for some plants. Algae tend to be both acid- and Al tolerant and, although some species may disappear with reduced pH, overall algae productivity and biomass are seldom affected if pH is above 3.0. Aluminum and acid toxicity tend to be additive to some algae when pH is less than 4.5. Because the metal binds with inorganic P, it may reduce P availability and reduce productivity. Forest die-backs in North America involving red spruce, Fraser fir, balsam fir, loblolly pine, slash pine, and sugar maples have been ascribed to Al toxicity, and extensive areas of European forests have died because of the combination of high soil Al and low pH. Extensive research on crops has produced Al-resistant cultivars and considerable knowledge about mechanisms of and defenses against toxicity. Very low Al levels may benefit some plants, although the metal is not recognized as an essential nutrient. Hyperaccumulator species of plants may concentrate Al to levels that are toxic to herbivores. Toxicity in aquatic invertebrates is also acid dependent. Taxa such as Ephemeroptera, Plecoptera, and Cladocera are sensitive and may perish when Al is less than 1 mg.L-1 whereas dipterans, molluscs, and isopods seem to be tolerant. In Al-sensitive species, elevated levels (approximately 500 micrograms.L-1) affect ion regulation and respiratory efficiency. Toxicity tends to be greatest near a species' threshold of pH sensitivity. At lower pHs, Al may have a slight ameliorative effect by interfering with H+ transport across membranes. Aquatic invertebrates can accumulate very high levels of Al, but most of this appears to be through adsorption rather than assimilation. Aluminum concentrations may be as high as 5000 mg.kg-1 in insects and greater than 17,000 mg.kg-1 in other invertebrates.(ABSTRACT TRUNCATED AT 400 WORDS)

Aluminum↗

Cerebriform (Sézary like) mononuclear cells in healthy individuals: a morphologically distinct population of T cells. Relationship with mycosis fungoides and Sézary's syndrome.

The ultrastructural and surface marker characteristics of lymphocytes in human cord blood and peripheral blood of healthy donors were studied with respect to the presence of cerebriform mononuclear cells similar to those occurring in the dermal infiltrate of patients with mycosis fungoides (mycosis cells), and the skin infiltrate and peripheral blood of patients with Sézary's syndrome (Sézary cells). Cerebriform monuclear (Sézary-like) cells are characterized by a high nucleus-cytoplasm ratio, deep and narrow nuclear identations, condensed chromatin at the nuclear membrane and cytoplasm poor in organelles. Of the lymphoid cells in human cord blood and peripheral blood of healthy donors 6.7 and 8.7% respectively proved to be cerebriform mononuclear cells. Since these cells invariably form E-rosettes they are part of the T-cell population in healthy individuals. The finding of similar cells in the skin infiltrate of patch test areas of patients allergic to rubber, formalin and peruvian balsam--an expression of cellular immunity mediated by T-cells--suggests that these cells are reactive T cells. Not all (up to 85%) of the cerebriform mononuclear cells in patients with mycosis fungoides and Sézary's syndrome have T-cell membrane characteristics as shown by E-rosette formation. This suggests the presence of two populations of cerebriform mononuclear cells in mycosis fungoides and Sézary's syndrome. The relationship of cerebriform T cells as seen in healthy individuals with cerebriform or atypical mononuclear cells occurring in the Sézary syndrome and mycosis fungoides is discussed.

Adolescent↗

[Contact allergies in patients with chronic wounds: results of a study from 1999 to 2004].

Patients with chronic wounds frequently acquire clinically relevant contact sensitization. We examined the results of the skin patch tests in patients with chronic wounds, who were treated between 1999-2004 in the Department of Dermatology, University School of Medicine, Essen, Germany. Altogether 105 patients with chronic wounds underwent patch testing. In 68 individuals, contact sensitization to at least one substance was detected. The most frequent contact allergens were to balsam of Peru, Amerchol L-101, fragrance mix, wool wax alcohols and rosins. Contact sensitization to wound dressing materials was also identified in 4 patients. Our results demonstrate the current spectrum of contact sensitization of patients with chronic wounds. Our results show the importance of paying attention to the ingredients in wound dressings and performing patch testing if there is any clinical suggestion of allergic contact dermatitis.

Adult↗

[Hematogenous contact eczema induced by foods].

Oral ingestion or parenteral administration of certain contact allergens may elicit eczematous skin reactions "from inside" in sensitized individuals; this phenomenon has been termed "systemically-induced eczema" or "hematogenous contact eczema". There is a wide range of clinical features from polyetiological dyshidrotic hand and foot eczema to baboon syndrome. The most important contact allergens known to elicit systemically-induced contact eczema are metal salts, drugs, phytoallergens and balsam of Peru. Diagnosis is based on proof of delayed type hypersensitivity by patch testing and oral challenge. Until more and better data is acquired, special diets (for instance low nickel) should be instituted only in carefully selected patients.

Dermatitis, Contact↗

Simultaneous determination of preservatives in beverages, vinegar, aqueous sauces, and quasi-drug drinks by stir-bar sorptive extraction (SBSE) and thermal desorption GC-MS.

A method for the simultaneous determination of seven preservatives - sorbic acid, benzoic acid, and p-hydroxybenzoic acid ethyl, isopropyl, propyl, isobutyl, and butyl esters - in beverages, vinegar, aqueous sauces, and quasi-drug drinks has been developed using the stir-bar sorptive extraction technique then thermal desorption GC-MS analysis. The extraction conditions - pH, sample volume, extraction temperature, salt addition, and extraction time - were examined. d5-Benzoic acid and p-hydroxybenzoic acid sec-butyl ester were added as surrogate internal standards to compensate for the effect of sample matrix and coexisting analytes on the sorptive extraction. The linearity of the method was good over the concentration range from 1 to 1000 microg mL(-1) for sorbic acid, 10-1000 microg mL(-1) for benzoic acid, and 0.1-100 microg mL(-1) for p-hydroxybenzoic acid ethyl, isopropyl, propyl, isobutyl, and butyl esters, and the correlation coefficients were higher than 0.9984. The limit of detection ranged from 0.015 to 3.3 microg mL(-1). The recoveries (95-105%) and precision (RSD: 0.86-6.0%) of the method were examined by analyzing a sparkling soft drink, white wine, red wine, balsamic vinegar, soy sauce, and quasi-drug drink samples fortified at the 5 to 50 microg mL(-1) level.

Acetic Acid↗

Relationships between stand composition and ectomycorrhizal community structure in boreal mixed-wood forests.

We investigated the community structure of ectomycorrhizal fungi under varying overstory tree compositions in the southern mixed-wood boreal forest of Quebec. Sampling took place at two locations of differing postfire ages and nine 100-m2 plots were sampled per location. The dominant overstory tree species in the plots were trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.) or white spruce [Picea glauca (Moench) Voss], and balsam fir [Abies balsamea (L.) Mill.]. Mycorrhizae were analyzed using morphological as well as molecular methods, employing fungal-specific primers to amplify ribosomal DNA for subsequent cloning and sequencing. A total of 1800 mycorrhizal root tips collected from the 18 plots were morphologically classified into 26 morphotypes, with Cenococcum geophilum dominating (36% of root tips). A second set of root tips, selected from the same 18 samples on which the morphological analysis was based, were analyzed using molecular methods. From this analysis, 576 cloned polymerase chain reaction products were screened by restriction fragment length polymorphism analysis and a total of 207 unique types were found. No one type dominated the system and 159 occurred only once. Sequence analysis of the types that occurred more than once revealed that Piloderma sp., Russula sp., Cortinarius sp., and Lactarius sp. were the most common mycorrhizae. The ectomycorrhizal fungal community structure revealed by the rDNA analysis differed from that observed using morphological methods. Canonical correspondence analyses of the sequenced restriction types and % overstory composition indicate that the distributions of ectomycorrhizal fungi are influenced by the relative proportions of host tree species. The distinct fungal assemblages found in the different plots supported by the different combinations of host tree species provides further support for the need to conserve stand diversity in the southern boreal forest.

DNA, Fungal↗

Occupational relevance of positive standard patch-test results in employed persons with an initial report of an occupational skin disease.

OBJECTIVES: It is commonly accepted that the standard screening tray is an essential diagnostic test in patch testing supporting the diagnosis of contact dermatitis, the most common type of occupational skin disease (OSD). In this study standard patch-test results of employed persons with an initial report of an OSD were analyzed within 24 occupational groups. METHODS: An evaluation was made of employed persons recorded in the Register of Occupational Skin Diseases in Northern Bavaria (Berufskrankheitenregister Haut-Nordbayern; BKH-N) between 1990 and 1999, catering for those standard screening tray allergens tested over the 10-year period. RESULTS: Nickel sulfate was the most common sensitizer (29.5%), showing occupational relevance in only 11% of the cases sensitized. Other common sensitizers were cobalt chloride (13.5%), p-phenylenediamine free base (10.7%), potassium dichromate (9.8%), fragrance mix (5.4%), thiuram mix (4.2%), balsam of Peru (4.0%), chloromethylisothiazolinone/methylisothiazolinone (4.0%), and formaldehyde (4.0%). The most occupationally relevant sensitizers were thiuram mix (71%), epoxy resin (67%), p-phenylenediamine free base (59%), p-phenylenediamine-black-rubber mix/ N-isopropyl- N'-phenyl- p-phenylenediamine (53%), potassium dichromate (48%), formaldehyde (38%), chloromethylisothiazolinone/methylisothiazolinone (37%), and mercapto-mix/mercaptobenzothiazole (35%). Occupational groups at risk of acquiring delayed-type sensitization were, in particular, electroplaters, tile setters and terrazzo workers, construction and cement workers, solderers, wood processors, and leather and fur processors. CONCLUSIONS: The standard series contributes valuable information and asserts its position in clarifying the causes of OSDs. Based on the study results, the rate of occupationally relevant sensitization to each single allergen is demonstrated, and the difficulties in verifying the occupational relevance are discussed.

Adult↗

Photopatch testing: the 5-year experience of the German, Austrian, and Swiss Photopatch Test Group.

A cooperative photopatch test study was conducted by 45 dermatologic centers in Austria, Germany, and Switzerland. Results obtained from 1985 to 1990 are presented. A standard photopatch test tray of 32 substances was applied to the back of patients with suspected photosensivity. After applications for 24 hours, test sites were irradiated with 10 joules/cm2UVA. Unirradiated controls were included. Readings were performed immediately and 24, 48, and 72 hours after irradiation; responses were qualitatively graded on a 4-point scale. All data were stored and processed by a computer. With computer-assisted analysis of reaction patterns photoallergic reactions were identified and distinguished from phototoxic reactions. Data of 1129 patients were evaluated. Among a total of 2859 positive test reactions in 870 patients, 2041 in 778 patients were found to be photoinduced and 818 in 413 patients were contact reactions; 108 reactions in 83 patients were classified as photoallergic. Nonsteroidal anti-inflammatory drugs, disinfectants, sunscreens, phenothiazines, and fragrances caused most often photoallergic reactions. Many unspecific phototoxic reactions were induced by tiaprofenic acid, promethazine, carprofen, chlorpromazine, fenticolar, wood balsam of Peru, and perfumes. Despite the distinction between photoallergic and phototoxic responses, many test reactions lacked relevance for the patients' dermatoses.

Adolescent↗

Sensitivity and specificity of Congo red staining according to Romhányi. Comparison with Puchtler's or Bennhold's methods.

The sensitivity and specificity of various Congo red staining methods is very important in the diagnosis of amyloidosis. When using a less sensitive staining method, some true positive cases of amyloidosis remain undetected. A more highly specific method potentially detects more cases and reveals amyloidosis in an earlier stage of deposition. In this paper, the Congo red staining method according to Romhányi is discussed in comparison with Puchtler's and Bennhold's methods. Using Romhányi's technique, there is no alcoholic differentiation, and thus no dye molecules are washed off the amyloid filaments. The binding of the oriented dye molecules is optimal for polarization microscopy. With this method, the polar hydrophilic mounting medium, gum Arabic is used. Mounted in this carbohydrate-containing, hydrophilic medium, the Congo red molecules are oriented parallel to the surface of the amyloid filaments and the sign is linear positive, corresponding to an additive character of topo-optical staining reactions. Otherwise, the Congo red molecules are oriented perpendicular to the surface of collagen, reducing the intensity of birefringence and even inducing an inversion of the original sign of the collagen birefringence. With alcoholic differentiation, Congo red dye molecules are extracted and this decreases the birefringence of amyloid deposits, i.e. minimal amyloid deposits may be missed. Using the apolar hydrophobic mounting medium, Canada balsam, an axis-parallel arrangement of Congo red dye molecules on the surface of collagen fibers and amyloid will occur, resulting in an additive topo-optical reaction with a green polarization color and a false positive diagnosis of amyloidosis ("phantom amyloidosis").

Amyloid↗