SYBR Green real-time reverse transcription-polymerase chain reaction assay for the generic detection of coronaviruses

Coronaviruses are etiologic agents of respiratory and enteric diseases in humans and in animals. In this study, a one-step real-time reverse transcription-polymerase chain reaction (RT-PCR) assay based on SYBR Green chemistry and degenerate primers was developed for the generic detection of coronaviruses. The primers, designed in the open reading frame 1b, enabled the detection of 32 animal coronaviruses including strains of canine coronavirus, feline coronavirus, transmissible gastroenteritis virus (TGEV), bovine coronavirus (BCoV), murine hepatitis virus (MHV) and infectious bronchitis virus (IBV). A specific amplification was also observed with the human coronaviruses (HCoV) HCoV-NL63, HCoV-OC43, HCoV-229E and severe acute respiratory syndrome coronavirus (SARS-CoV). The real-time RT-PCR detected down to 10 cRNA copies from TGEV, BCoV, SARS-CoV and IBV. In addition, the assay exhibited a high sensitivity and specificity on clinical samples from different animal species. The developed assay represents a potential tool for laboratory diagnostics and for detecting still uncharacterized coronaviruses.

GABA-site antagonism and pentobarbital actions do not depend on the alpha-subunit type in the recombinant rat GABA receptor

AIM

The roles of alpha-subunits on the gamma-aminobutyric acid (GABA)-site antagonism and pentobarbital actions were examined in rat recombinant GABA(A) receptors in Xenopus oocytes.

METHODS

Experiments were performed with binary and ternary GABA(A) receptors containing alpha1-, alpha4- or alpha5-subunit by the two-electrode voltage-clamp technique.

RESULTS

The potency of GABA was significantly higher in the alpha1beta2, alpha4beta2 and alpha5beta2 receptors compared with the alpha1beta2gamma2L, alpha4beta2gamma2L and alpha5beta2gamma2L receptors. However, the alpha5beta2 receptor possessed significantly lower GABA efficacy compared with the alpha5beta2gamma2L receptor. While the gamma2-subunit was essential to the potency of GABA, its influence on the apparent GABA-site antagonism was less profound. The antagonist affinity constants (K(B)) of bicuculline inhibition and slopes of Schild plots were similar between all types of ternary and binary receptors except alpha5beta2 receptor which was not tested. The pK(B)s and IC(50)s of the GABA-site antagonism were not significantly different between the alpha1beta2gamma2L, alpha4beta2gamma2L and alpha5beta2gamma2L receptors. Bicuculline blocked pentobarbital-activated currents in a reversible and non-competitive manner with the alpha1beta2gamma2L, alpha4beta2gamma2L, and alpha5beta2gamma2L receptors, indicating an allosteric inhibition of the GABA-site. No significant difference of bicuculline potencies in inhibiting GABA- and pentobarbital-activated currents was found between the alpha1beta2gamma2L, alpha4beta2gamma2L and alpha5beta2gamma2L receptors.

CONCLUSION

The GABA-site antagonism does not depend on the subtype of alpha-subunits. Similarly, pentobarbital activates ternary receptors composed of different alpha-subunits in a bicuculline-sensitive manner. The potencies of bicuculline to inhibit pentobarbital-activated currents are identical with receptors containing alpha1, alpha4 or alpha5-subunit. The alpha1beta2 and alpha4beta2 receptors possess higher GABA potencies compared with the alpha1beta2gamma2L and alpha4beta2gamma2L receptors.

Contact allergy to textile dyes in southern Sweden

Contact allergy to disperse dyes in textiles is documented in prevalence studies from southern Europe. To evaluate the prevalence of allergic patch test reactions to different textile dyes in southern Sweden, and to look at the sites of dermatitis in individuals hypersensitive to textile dyes, we retrospectively investigated 3325 consecutively patch-tested patients. They had all been patch tested with the standard test series supplemented with a textile dye mix (TDM) consisting of 8 disperse dyes, i.e. Disperse (D) Blue 35, 106 and 124, D Yellow 3, D Orange 1 and 3 and D Red 1 and 17. All but 3 of the TDM-positive patients were additionally tested with the separate dyes included in the mix. The frequency of contact allergy to TDM was 1.5%, which is comparable with studies from southern Europe. The most common dye allergen was D Orange 1. The high prevalence of allergic reactions to D Orange 1 was unexpected, whereas test reactions to D Blue 106 and 124 were lower than expected from other studies. Compared to all tested patients, the TDM-positive patients more often had dermatitis on their arms, face, neck and axillary folds, and women also had a higher frequency of hand dermatitis.

Can an imidazolidinyl urea-preserved corticosteroid cream be safely used in individuals hypersensitive to formaldehyde?

A topical corticosteroid preparation on the Swedish market, Flutivate cream, contains a fairly high concentration of formaldehyde (FA). In this study, we have investigated the clinical relevance of contact allergy to FA when treating an allergic eczema with Flutivate cream, containing an FA-releasing preservative. In a randomized, double-blind study, 7 patients hypersensitive to both FA and nickel repeatedly applied Flutivate cream containing FA or Betnovate cream not containing FA to areas of experimentally induced nickel dermatitis. 17 controls allergic to nickel, but not FA, went through the same procedure. In 29 per cent of the FA-allergic individuals, the experimental dermatitis healed when treated with Flutivate cream compared with 71 per cent of the controls (P = 0.04). The conclusion to draw from this study is that an individual hypersensitive to FA should not use the corticosteroid preparation Flutivate cream on dermatitis skin.

The development and course of patch-test reactions to 2-hydroxyethyl methacrylate and ethyleneglycol dimethacrylate

Because Methacrylic monomers are used in dental work, dental personnel, technicians, and patients are at risk of being sensitized. 2-hydroxyethyl methacrylate (2-HEMA) and ethyleneglycol dimethacrylate (EGDMA) are commonly used. Allergic test reactions to them sometimes appear beyond D7. This study was designed to study the development and course of positive test reactions to 2-HEMA and EGDMA in allergic patients as a mean to elucidate the issue of patch-test sensitization. 12 patients with contact allergy to 2-HEMA and EGDMA were retested with dilution series. The clinical course was followed for 1 month. During the study, 25 positive test reactions to 2-HEMA and 19 to EGDMA were diagnosed. Within the 1st week, 21 were noted for 2-HEMA and 18 for EGDMA. After 10 days, another 2 reactions appeared for 2-HEMA and 1 for EGDMA. All but 1 patient with the latter reactions also had positive reactions within the 1st week. After 1 month, 12 reactions for 2-HEMA and 10 for EGDMA remained. Patch-test reactions to 2-HEMA and EGDMA are long-lasting. The patch-test concentrations of 2.0% for 2-HEMA and EGDMA may be continually used. Positive test reactions emerging after 10 days do not automatically imply active sensitization.

Chemical analysis of 2,4-toluene diisocyanate, 1,6-hexamethylene diisocyanate and isophorone diisocyanate in petrolatum patch-test preparations

BACKGROUND

Isocyanates with the general formula R-(N=C=O) are theoretically contact sensitizers. However, allergic contact dermatitis (ACD) from isocyanates is seldom reported. In previous reports, patients reacted to their isocyanate-based work materials but not to commercial patch-test preparations of isocyanates. Therefore, we suspected that the low frequency of reported ACD from isocyanates was partly due to inadequate commercial preparations. A past study also showed the concentrations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI) in petrolatum preparations to be much lower than declared.

OBJECTIVE

In this study, 2,4-toluene diisocyanate (2,4-TDI), 1,6-hexamethylene diisocyanate (1,6-HDI), and isophorone diisocyanate (IPDI) were investigated in a similar fashion.

METHODS

In preparations from 12 dermatology departments and two suppliers of patch-test allergens, we determined the isocyanate content as the isocyanate-dibutylamine derivative, using liquid chromatography and mass spectrometry. The preparations were considered stable if the ratio between the stated and found concentrations was within the range of 0.8 to 1.2.

RESULTS

Although 28 of 36 investigated preparations had ratios outside of the stable range, they were in its vicinity, which indicates that preparations of 2,4-TDI, 1,6-HDI, and IPDI are more stable than are preparations of 4,4'-MDI where previously reported results showed ratios far outside of stable range.

CONCLUSION

As opposed to preparations of 4,4'-MDI, preparations of 2,4-TDI, 1,6-HDI, and IPDI can be considered to be stable.

Risk of contact allergy and dermatitis at a wind turbine plant using epoxy resin-based plastics

AIMS

To identify workplace and individual risk factors for occupational contact allergy and dermatitis.

METHODS

A cross-sectional study was carried out at an international company producing wind turbine systems in Denmark. A cohort of 724 production workers at four facilities was highly exposed to epoxy resin as well as other chemicals. A screening questionnaire (participation rate 84.7%) was followed by an interview by an occupational physician and a dermatological examination, including patch testing, for a comprehensive list of potential workplace sensitizers.

RESULTS

Clinically diagnosed dermatitis was found among 214 workers (35.8%) and contact allergy to materials used in the workplace was found in 66 workers (10.9% of the total population and 20.3% of those who underwent patch testing). Of the 66 workers with a work-related allergy, 40 (60.6%) were allergic to epoxy compounds, 25 (37.9%) to hardeners and ten (15.2%) to other workplace materials, where one person showed an allergy only to these materials. Experiencing contact allergy was related to older age and longer employment in the workplace-however, neither of these risk factors was significant. The main risk factor for current dermatitis was contact allergy to materials used in the workplace, determined by patch testing, OR=5.4 (95% CI 3.9-9.9). Fewer days of absence from work was also related to current dermatitis, OR=2.0 (95% CI 1.2-3.5).

CONCLUSIONS

In a cohort of workers with extensive exposure to chemicals related to epoxy-resin systems, contact dermatitis and allergy was prevalent. Older age and longer duration of employment at the workplace were individual risk factors for allergy to workplace materials, whilst work-related allergies and longer duration of employment at the workplace were significant risk factors for current dermatitis.

Poor correlation between stated and found concentrations of diphenylmethane-4,4'-diisocyanate (4,4'-MDI) in petrolatum patch-test preparations

Diphenylmethane diisocyanate (MDI) is widely used in its polymeric form in the manufacturing of polyurethane products. Previous reports on MDI-related contact allergy have shown a pattern, where patients seem to react to their own MDI-based work material but not to commercial patch-test preparations, which contain 4,4'-MDI. Therefore, we performed chemical analyses of 14 commercial test preparations of 4,4'-MDI obtained from 8 European and 4 American dermatology departments as well as 2 preparations from 2 major European suppliers of patch-test allergens. A new method for monitoring 4,4'-MDI in petrolatum preparations was developed and the determination of 4,4'-MDI as the MDI-dibutylamine derivative using liquid chromatography-mass spectrometry was performed. None of the preparations obtained from the dermatology departments contained more than 12% of the concentration stated on the label. In most cases, 4,4'-MDI content was only a few percentages or less of the concentration stated. 7 of the 14 preparations were analysed before the expiry date. Yet, only 1 of them, a preparation directly obtained from the supplier, came close to the concentration stated on the label. Thus, using these preparations, patients will be tested with a lower concentration than intended, leading to possible false-negative reactions.

Corticosteroids

Up to 5% of dermatitis patients are allergic to corticosteroids. Because such allergy may be difficult to suspect due to the anti-inflammatory action of the corticosteroid, markers for corticosteroid allergy should be present in any standard series. Budesonide and tixocortol pivalate are two such markers, and they seem to detect a majority of corticosteroid allergy. The patch test concentration for a given corticosteroid may be crucial. A false-negative reaction may follow despite the patient being allergic, if too high a test concentration is used, because of the anti-inflammatory action of the corticosteroid. Patch test readings must be performed not only on Day 3 or Day 4 but also on a late occasion, i.e., Day 7 after test application, also because the anti-inflammatory action may suppress an allergic reaction at an early reading. Once a patient has reacted to a corticosteroid, an extended corticosteroid series should be tested, so that information may be given on which corticosteroids to use and, above all, which corticosteroids to avoid.

Occupational contact allergy and dermatitis from methylisothiazolinone after contact with wallcovering glue and after a chemical burn from a biocide

Skin exposure to biocides containing high concentrations of methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) may cause severe chemical burns and may also induce sensitization. We report two cases in which skin exposure to a newly launched biocide containing 2-methyl-4-isothiazolin-3-one (MI) and 1,2-benzisothiazolin-3-one led to sensitization to Ml, which in the second case was preceded by a chemical burn. A study was performed to investigate the pattern of reactivity to MCI and Ml in two patients who presumably had a primary sensitization to Ml and in one patient who had been sensitized to MCI/MI by being patch-tested. The patients were patch-tested with serial dilutions of MCI/MI, MCI, MI, and 2-n-octyl-4-isothiazolin-3-one. The first two patients reacted to both MCI/MI and the separate active ingredients, with a higher level of reactivity to Ml than to MCI. The third patient reacted to MCI/MI and MCI only. A biocide containing Ml caused sensitization and occupational contact dermatitis in the first two patients, through contact with wallpaper glue in one case and after a chemical burn in the other case.

Persistent itching nodules after the fourth dose of diphtheria–tetanus toxoid vaccines without evidence of delayed hypersensitivity to aluminium

Studies in Gothenburg, Sweden, reported an exceptionally high rate of persistent itching nodules at the site of injection of aluminium containing vaccines, usually with positive epicutaneous tests to aluminium. When a new booster diphtheria-tetanus vaccine was introduced we performed a prospective cluster randomised active surveillance in 25,232 10-year-olds. Parental reports 6 months after vaccination with Duplex or diTeBooster were collected for 22,365 (88%) pupils in 851 schools. We identified 3-6 children per 10,000 with a local itching nodule persisting for at least 2 months. There were no significant differences between the vaccine groups. Contact allergy to aluminium was not detected. The findings support the use of the vaccine presently available in the Swedish vaccination program. Continued surveillance of persistent itching nodules and aluminium contact allergy is, however, warranted for vaccines containing pertussis toxoid and aluminium.

Retained heterodisomy for chromosome 12 in atypical lipomatous tumors: implications for ring chromosome formation

Atypical lipomatous tumor (ALT) is an intermediate malignant mesenchymal tumor that is characterized by supernumerary ring chromosomes and/or giant rod-shaped marker chromosomes (RGMC). Fluorescence in situ hybridization (FISH) and molecular genetic analyses have disclosed that the RGMCs always contain amplified sequences from the long arm of chromosome 12. Typically, RGMCs are the sole clonal changes and so far no deletions or other morphologic aberrations of the two normal-appearing chromosomes 12 that invariably are present have been detected. The mechanisms behind the formation of the RGMCs are unknown, but it could be hypothesized that RGMC formation is preceded by trisomy 12 or, alternatively, that ring formation of one chromosome 12 is followed by duplication of the remaining homolog. The latter scenario would always result in isodisomy for the two normal-appearing chromosomes 12, whereas the former would yield isodisomy in one-third of the cases. In order to investigate these possible mechanisms behind ring formation, we studied polymorphic loci on chromosome 12 in 14 cases of ALT showing one or more supernumerary ring chromosomes and few or no other clonal aberrations at cytogenetic analysis. The molecular genetic analyses showed that the tumor cells always retained both parental copies of chromosome 12, thus refuting the trisomy 12 and duplication hypotheses.

Epoxy-based production of wind turbine rotor blades: occupational dermatoses

Occupational dermatoses were investigated in a factory producing rotor blades for wind turbines by an epoxy-based process. In a blinded study design, 603 workers were first interviewed and thereafter clinically examined. Based on a history of work-related skin disease, clinical findings of dermatitis, or both, 325 (53.9%) of the workers were patch tested with a specially profiled occupational patch-test series and the European standard patch-test series. Calculated on all investigated workers, 17.1% of the workers were diagnosed with occupational dermatoses caused by work. Occupational allergic contact dermatitis was found in 10.9% of the workers. The estimated frequency of irritant contact dermatitis caused by work was 6.1%. Dermatitis on the hands was associated with contact allergy to epoxy resin (P = 0.017). The number of days on leave before the clinical examination was negatively associated with the presence of dermatitis (P = 0.001). Among workers employed 7-12 months, the frequency of occupational contact allergy was higher than that among workers employed for </=6 months (P = 0.004). Females both washed their hands more often (P < 0.001) and used more moisturizers/protection creams at work (P < 0.001) than males. No sex differences were found concerning dermatitis on the hands.

Oral prednisone suppresses allergic but not irritant patch test reactions in individuals hypersensitive to nickel

A multicentre, randomized, double-blind, crossover study was designed to investigate the effects of prednisone on allergic and irritant patch test reactions. 24 subjects with known allergy to nickel were recruited and patch tested with a nickel sulfate dilution series in aqueous solution, 5% nickel sulfate in petrolatum and 2 dilution series of the irritants nonanoic acid and sodium lauryl sulfate. The subjects were tested x2, both during treatment with prednisone 20 mg oral daily and during placebo treatment. The total number of positive nickel patch test reactions decreased significantly in patients during prednisone treatment. The threshold concentration to elicit a patch test reaction increased and the overall degree of reactivity to nickel sulfate shifted towards weaker reactions. The effect of prednisone treatment on the response to irritants was divergent with both increased and decreased numbers of reactions, although there were no statistically significant differences compared with placebo. It is concluded that oral treatment with prednisone suppresses patch test reactivity to nickel, but not to the irritants tested.

Photoallergic contact dermatitis from ketoprofen induced by drug-contaminated personal objects

BACKGROUND

Photoallergic contact dermatitis from ketoprofen has been recognized since the mid-1980s. Skin reactions have been reported to continue weeks after discontinuation of ketoprofen. One reason for this could be residual ketoprofen in the skin, which has been shown in a skin biopsy specimen.

OBJECTIVE

We sought to report on 3 cases of photoallergic contact dermatitis from ketoprofen in topical anti-inflammatory gels and on relapses of dermatitis appearing after use of ketoprofen-contaminated objects.

METHODS

We patch and photopatch tested, with standard series, the anti-inflammatory gel, ketoprofen, and its ingredients in serial dilutions and extracts of personal objects. We performed chemical investigations of personal objects with thin-layer chromatography, high-pressure liquid chromatography, and gas chromatography-mass spectrometry.

RESULTS

Photoallergy was demonstrated to ketoprofen, which was detected in personal objects.

CONCLUSION

Relapses of photoallergic contact dermatitis in patients photoallergic to ketoprofen can be induced by ketoprofen-contaminated objects such as bandages and slippers.

Occupational Contact Dermatitis from a Grease

BACKGROUND

Contact allergy to grease is rare and often not even suspected. We investigated such a case in which the detected allergen was the stabilizer in the grease, which is rarely found as an allergen.

OBJECTIVE

Thin-layer chromatography (TLC) was used in a novel way and helped detect the allergen.

METHODS

Patch testing with our standard series, a metal-working series, the different substances individually, the grease in serial dilution and extracts of personal objects, the TLC plate. Gas chromatography-mass spectrometry was also used.

RESULTS

Test results indicated contact allergy to grease containing N-phenyl-1-naphthylamine and contact allergy to Disperse Orange 1, N-cyclohexyl-N'-phenyl-4-phenylenediamine, N-isopropyl-N'-phenyl-4-phenylenediamine, and N,N'-diphenyl-4-phenylenediamine.

CONCLUSION

N-phenyl-1-naphthylamine was the main cause of the patient's dermatitis. This case report underlines the importance of testing the patient's own products and also underlines the benefit of using TLC strips for patch testing and of visiting the workplace to get correct information about exposure conditions.

Epoxy-Based Production of Wind Turbine Rotor Blades: Occupational Contact Allergies

BACKGROUND

An industry producing rotor blades for wind turbines with an epoxy-based technology had experienced an increasing number of workers with dermatitis, among whom the frequency of occupational contact allergy (OCA) was suspected to be underestimated.

OBJECTIVE

To investigate the frequency of OCA by patch-testing with a specially profiled occupational patch test series.

METHODS

In a blinded study design, 603 workers were first interviewed and thereafter clinically examined. Based on a history of work-related skin disease, clinical findings of dermatitis, or both, 325 (53.9%) of the workers were patch-tested with an occupational patch test series and the European Standard patch test series.

RESULTS

Of the 603 investigated workers, 10.9% had OCA and 5.6% had contact allergy to epoxy resin in the standard test series. Contact allergy to amine hardeners/catalysts was found in 4.1% of the workers. Among the workers with OCA, 48.5% reacted to work material other than epoxy resin in the European Standard patch test series.

CONCLUSION

Approximately 50% of the workers with OCA would not have been detected if only the European Standard patch test series had been used.