RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays

Tools for radiation exposure reconstruction are required to support the medical management of radiation victims in radiological or nuclear incidents. Different biological and physical dosimetry assays can be used for various exposure scenarios to estimate the dose of ionizing radiation a person has absorbed. Regular validation of the techniques through inter-laboratory comparisons (ILC) is essential to guarantee high quality results. In the current RENEB inter-laboratory comparison, the performance quality of established cytogenetic assays [dicentric chromosome assay (DCA), cytokinesis-block micronucleus assay (CBMN), stable chromosomal translocation assay (FISH) and premature chromosome condensation assay (PCC)] was tested in comparison to molecular biological assays [gamma-H2AX foci (gH2AX), gene expression (GE)] and physical dosimetry-based assays [electron paramagnetic resonance (EPR), optically or thermally stimulated luminescence (LUM)]. Three blinded coded samples (e.g., blood, enamel or mobiles) were exposed to 0, 1.2 or 3.5 Gy X-ray reference doses (240 kVp, 1 Gy/min). These doses roughly correspond to clinically relevant groups of unexposed to low exposed (0-1 Gy), moderately exposed (1-2 Gy, no severe acute health effects expected) and highly exposed individuals (>2 Gy, requiring early intensive medical care). In the frame of the current RENEB inter-laboratory comparison, samples were sent to 86 specialized teams in 46 organizations from 27 nations for dose estimation and identification of three clinically relevant groups. The time for sending early crude reports and more precise reports was documented for each laboratory and assay where possible. The quality of dose estimates was analyzed with three different levels of granularity, 1. by calculating the frequency of correctly reported clinically relevant dose categories, 2. by determining the number of dose estimates within the uncertainty intervals recommended for triage dosimetry (±0.5 Gy or ±1.0 Gy for doses <2.5 Gy or >2.5 Gy), and 3. by calculating the absolute difference (AD) of estimated doses relative to the reference doses. In total, 554 dose estimates were submitted within the 6-week period given before the exercise was closed. For samples processed with the highest priority, earliest dose estimates/categories were reported within 5-10 h of receipt for GE, gH2AX, LUM, EPR, 2-3 days for DCA, CBMN and within 6-7 days for the FISH assay. For the unirradiated control sample, the categorization in the correct clinically relevant group (0-1 Gy) as well as the allocation to the triage uncertainty interval was, with the exception of a few outliers, successfully performed for all assays. For the 3.5 Gy sample the percentage of correct classifications to the clinically relevant group (≥2 Gy) was between 89-100% for all assays, with the exception of gH2AX. For the 1.2 Gy sample, an exact allocation to the clinically relevant group was more difficult and 0-50% or 0-48% of the estimates were wrongly classified into the lowest or highest dose categories, respectively. For the irradiated samples, the correct allocation to the triage uncertainty intervals varied considerably between assays for the 1.2 Gy (29-76%) and 3.5 Gy (17-100%) samples. While a systematic shift towards higher doses was observed for the cytogenetic-based assays, extreme outliers exceeding the reference doses 2-6 fold were observed for EPR, FISH and GE assays. These outliers were related to a particular material examined (tooth enamel for EPR assay, reported as kerma in enamel, but when converted into the proper quantity, i.e. to kerma in air, expected dose estimates could be recalculated in most cases), the level of experience of the teams (FISH) and methodological uncertainties (GE). This was the first RENEB ILC where everything, from blood sampling to irradiation and shipment of the samples, was organized and realized at the same institution, for several biological and physical retrospective dosimetry assays. Almost all assays appeared comparably applicable for the identification of unexposed and highly exposed individuals and the allocation of medical relevant groups, with the latter requiring medical support for the acute radiation scenario simulated in this exercise. However, extreme outliers or a systematic shift of dose estimates have been observed for some assays. Possible reasons will be discussed in the assay specific papers of this special issue. In summary, this ILC clearly demonstrates the need to conduct regular exercises to identify research needs, but also to identify technical problems and to optimize the design of future ILCs.

RENEB Inter-Laboratory Comparison 2021: The Dicentric Chromosome Assay

After large-scale radiation accidents where many individuals are suspected to be exposed to ionizing radiation, biological and physical retrospective dosimetry assays are important tools to aid clinical decision making by categorizing individuals into unexposed/minimally, moderately or highly exposed groups. Quality-controlled inter-laboratory comparisons of simulated accident scenarios are regularly performed in the frame of the European legal association RENEB (Running the European Network of Biological and Physical retrospective Dosimetry) to optimize international networking and emergency readiness in case of large-scale radiation events. In total 33 laboratories from 22 countries around the world participated in the current RENEB inter-laboratory comparison 2021 for the dicentric chromosome assay. Blood was irradiated in vitro with X rays (240 kVp, 13 mA, ∼75 keV, 1 Gy/min) to simulate an acute, homogeneous whole-body exposure. Three blood samples (no. 1: 0 Gy, no. 2: 1.2 Gy, no. 3: 3.5 Gy) were sent to each participant and the task was to culture samples, to prepare slides and to assess radiation doses based on the observed dicentric yields from 50 manually or 150 semi-automatically scored metaphases (triage mode scoring). Approximately two-thirds of the participants applied calibration curves from irradiations with γ rays and about 1/3 from irradiations with X rays with varying energies. The categorization of the samples in clinically relevant groups corresponding to individuals that were unexposed/minimally (0-1 Gy), moderately (1-2 Gy) or highly exposed (>2 Gy) was successfully performed by all participants for sample no. 1 and no. 3 and by ≥74% for sample no. 2. However, while most participants estimated a dose of exactly 0 Gy for the sham-irradiated sample, the precise dose estimates of the samples irradiated with doses >0 Gy were systematically higher than the corresponding reference doses and showed a median deviation of 0.5 Gy (sample no. 2) and 0.95 Gy (sample no. 3) for manual scoring. By converting doses estimated based on γ-ray calibration curves to X-ray doses of a comparable mean photon energy as used in this exercise, the median deviation decreased to 0.27 Gy (sample no. 2) and 0.6 Gy (sample no. 3). The main aim of biological dosimetry in the case of a large-scale event is the categorization of individuals into clinically relevant groups, to aid clinical decision making. This task was successfully performed by all participants for the 0 Gy and 3.5 Gy samples and by 74% (manual scoring) and 80% (semi-automatic scoring) for the 1.2 Gy sample. Due to the accuracy of the dicentric chromosome assay and the high number of participating laboratories, a systematic shift of the dose estimates could be revealed. Differences in radiation quality (X ray vs. γ ray) between the test samples and the applied dose effect curves can partly explain the systematic shift. There might be several additional reasons for the observed bias (e.g., donor effects, transport, experimental conditions or the irradiation setup) and the analysis of these reasons provides great opportunities for future research. The participation of laboratories from countries around the world gave the opportunity to compare the results on an international level.

Peanut-induced anaphylaxis in children and adolescents: Data from the European Anaphylaxis Registry

BACKGROUND

Peanut allergy has a rising prevalence in high-income countries, affecting 0.5%-1.4% of children. This study aimed to better understand peanut anaphylaxis in comparison to anaphylaxis to other food triggers in European children and adolescents.

METHODS

Data was sourced from the European Anaphylaxis Registry via an online questionnaire, after in-depth review of food-induced anaphylaxis cases in a tertiary paediatric allergy centre.

RESULTS

3514 cases of food anaphylaxis were reported between July 2007 - March 2018, 56% in patients younger than 18 years. Peanut anaphylaxis was recorded in 459 children and adolescents (85% of all peanut anaphylaxis cases). Previous reactions (42% vs. 38%; p = .001), asthma comorbidity (47% vs. 35%; p < .001), relevant cofactors (29% vs. 22%; p = .004) and biphasic reactions (10% vs. 4%; p = .001) were more commonly reported in peanut anaphylaxis. Most cases were labelled as severe anaphylaxis (Ring&Messmer grade III 65% vs. 56% and grade IV 1.1% vs. 0.9%; p = .001). Self-administration of intramuscular adrenaline was low (17% vs. 15%), professional adrenaline administration was higher in non-peanut food anaphylaxis (34% vs. 26%; p = .003). Hospitalization was higher for peanut anaphylaxis (67% vs. 54%; p = .004).

CONCLUSIONS

The European Anaphylaxis Registry data confirmed peanut as one of the major causes of severe, potentially life-threatening allergic reactions in European children, with some characteristic features e.g., presence of asthma comorbidity and increased rate of biphasic reactions. Usage of intramuscular adrenaline as first-line treatment is low and needs to be improved. The Registry, designed as the largest database on anaphylaxis, allows continuous assessment of this condition.

Realising the European network of biodosimetry: RENEB-status quo

Creating a sustainable network in biological and retrospective dosimetry that involves a large number of experienced laboratories throughout the European Union (EU) will significantly improve the accident and emergency response capabilities in case of a large-scale radiological emergency. A well-organised cooperative action involving EU laboratories will offer the best chance for fast and trustworthy dose assessments that are urgently needed in an emergency situation. To this end, the EC supports the establishment of a European network in biological dosimetry (RENEB). The RENEB project started in January 2012 involving cooperation of 23 organisations from 16 European countries. The purpose of RENEB is to increase the biodosimetry capacities in case of large-scale radiological emergency scenarios. The progress of the project since its inception is presented, comprising the consolidation process of the network with its operational platform, intercomparison exercises, training activities, proceedings in quality assurance and horizon scanning for new methods and partners. Additionally, the benefit of the network for the radiation research community as a whole is addressed.

Curcumin and trans-resveratrol exert cell cycle-dependent radioprotective or radiosensitizing effects as elucidated by the PCC and G2-assay

Curcumin and trans-resveratrol are well-known antioxidant polyphenols with radiomodulatory properties, radioprotecting non-cancerous cells while radiosensitizing tumor cells. This dual action may be the result of their radical scavenging properties and their effects on cell-cycle checkpoints that are activated in response to radiation-induced chromosomal damage. It could be also caused by their effect on regulatory pathways with impact on detoxification enzymes, the up-regulation of endogenous protective systems, and cell-cycle-dependent processes of DNA damage. This work aims to elucidate the mechanisms underlying the dual action of these polyphenols and investigates under which conditions they exhibit radioprotecting or radiosensitizing properties. The peripheral blood lymphocyte test system was used, applying concentrations ranging from 1.4 to 140μM curcumin and 2.2 to 220μM trans-resveratrol. The experimental design focuses first on their radioprotective effects in non-cycling lymphocytes, as uniquely visualized using cell fusion-mediated premature chromosome condensation, excluding, thus, cell-cycle interference to repair processes and activation of checkpoints. Second, the radiosensitizing potential of these chemicals on the induction of chromatid breaks in cultured lymphocytes following G2-phase irradiation was evaluated by a standardized G2-chromosomal radiosensitivity predictive assay. This assay uses caffeine for G2-checkpoint abrogation and it was applied to obtain an internal control for radiosensitivity testing, which simulates conditions similar to those of the highly radiosensitive lymphocytes of AT patients. The results demonstrate for the first time the cell-cycle-dependent action of these polyphenols. When non-cycling cells are irradiated, the radioprotective properties of curcumin and trans-resveratrol are more prominent. However, when cycling cells are irradiated during G2-phase, the radiosensitizing features of these compounds are more pronounced. This observation offers a new biological basis for the mechanisms underlying the action of these polyphenols in cancer radiotherapy.

[Evaluation of postoperative myocardial injury by heart-type fatty acid-binding protein in off-pump coronary artery bypass grafting surgery]

BACKGROUND AND GOAL OF STUDY

Postoperative myocardial infarction is a serious and frequent complication of cardiac surgery. Nonetheless, diagnosis in this context it is occasionally challenging. We sought to evaluate the kinetics and diagnostic accuracy of the new biomarker « heart-type fatty acid-binding protein » (h-FABP) in the early detection of myocardial injury in patients undergoing off-pump coronary artery bypass grafting, compared with classical biomarkers.

MATERIALS AND METHODS

A prospective study was conducted on 17 consecutive patients who underwent off-pump coronary artery bypass grafting during a 2 month period. Blood samples were drawn for measurement of myocardial ischemic injury biomarkers (h-FABP, troponin, creatine kinase [CK] and CK-MB), at baseline (T1), immediate post-coronary artery bypass grafting (T2), on ICU admission (T3), and after 4 (T4), 8 (T5), 24 (T6) and 48 h (T7). Perioperative ischemic complications, defined according to electrocardiographic, echocardiographic and hemodynamic criteria, were recorded.

RESULTS

Earlier biomarkers peak plasma values occurred at T4 with troponin (2.9 ± 5.2 ng/mL), and at T5 with h-FABP (37.9 ± 55.5 ng/mL). Maximum values of CK and CK-MB occurred later, both in T6 (741 ± 779 and 37 ± 51 U/L, respectively). The optimized cut-off obtained for h-FABP was 19 ng/mL, providing a sensitivity and specificity of 77 and 75%, respectively, for diagnosis of perioperative ischemic injury, with an area under the ROC curve for h-FABP of 0.83 (95% CI 0.6-1.0) vs. 0.63 (95% CI 0.33-0.83) for troponin. This cut-off value for h-FABP is reached on average at T2 (mean value of h-FABP at T2: 18.9 ± 21.5 ng/mL).

CONCLUSION

This is the first study evaluating the kinetics of h-FABP biomarker in perioperative off-pump coronary artery bypass grafting, and the cut-off value established could help to extend earlier detection of myocardial ischemia in this context.

Realising the European Network of Biodosimetry (RENEB)

In Europe, a network for biological dosimetry has been created to strengthen the emergency preparedness and response capabilities in case of a large-scale nuclear accident or radiological emergency. Through the RENEB (Realising the European Network of Biodosimetry) project, 23 experienced laboratories from 16 European countries will establish a sustainable network for rapid, comprehensive and standardised biodosimetry provision that would be urgently required in an emergency situation on European ground. The foundation of the network is formed by five main pillars: (1) the ad hoc operational basis, (2) a basis of future developments, (3) an effective quality-management system, (4) arrangements to guarantee long-term sustainability and (5) awareness of the existence of RENEB. RENEB will thus provide a mechanism for quick, efficient and reliable support within the European radiation emergency management. The scientific basis of RENEB will concurrently contribute to increased safety in the field of radiation protection.

Biological and physical methods for risk estimation in interventional radiology: a detrimental effect approach

Interventional radiologists and staff members are frequently exposed to the effects of direct and scattered radiation, which undergo in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using termoluminiscence dosimeters (TLD's) and wrist dosimeters, H(p)(10) and H(p)(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03 × 10(-3), 5.06 × 10(-2)], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84 × 10(-2), 3.36 × 10(-1)], and using biological doses, of [1.40 × 10(-1), 1.51], which is considerably higher than incidence rates, showing an excess radio-induced risk of leukemia in the group under study. Finally, the maximum radiological detriment in the group, evaluated as the total number of radio-induced cancers using physical dosimetry, has been of 2.18 per 1000 person-year (skin and leukemia), and using biological dosimetry of 9.20 per 1000 PY (leukemia). As a conclusion, this study has provided an assessment of the non-deterministic effects (rate of radio-induced cancer incidence) attributable to the group under study due to their professional activity.

Unexplained overexposures on physical dosimetry reported by biological dosimetry

The Medical Service of the Radiation Protection Service from the University Hospital La Fe (Valencia, Spain), carries out medical examinations of the workers occupationally exposed to ionising radiation. The Biological Dosimetry Laboratory is developing its activity since 2001. Up to now, the activities have been focused in performing biological dosimetry studies of Interventionists workers from La Fe Hospital. Recently, the Laboratory has been authorized by the Health Authority in the Valencian Community. Unexplained overexposures of workers and patients are also studied. Workers suspected of being overexposed to ionising radiation were referred for investigation by cytogenetic analysis. Two of these were from Hospitals of the Valencian Community and one belonged to an uranium mine from Portugal. Hospital workers had a physical dose by thermoluminiscence dosimeters (TLD) that exceeded the established limit. The worker of the uranium mine received a dose from a lost source of Cesium 137 with an activity of 170 mCi. All three cases showed normal values after the hematological analysis. Finally, the aim of this study consist to determine whether the dose showed by the dosimeter is reliable or not. In the case of workers that wore dosimeter, it is concluded that the doses measured by dosimeter are not corresponding to real doses. Hospital worker with a physical dose of 2.6 Sv and 0.269 Sv had an estimated absorbed dose by biological dosimetry of 0.076 Gy (0-0.165 Gy) and 0 Gy (0-0.089 Gy), respectively. In case of the mine worker an estimated absorbed dose of 0.073 Gy (0-0.159 Gy) was obtained by biological dosimetry. In all cases we used the odds ratio to present the results due to a very low frequency of observed aberrations [1].

Radiation effects analysis in a group of interventional radiologists using biological and physical dosimetry methods

Interventional radiologists and staff members are frequently exposed to protracted and fractionated low doses of ionizing radiation, which extend during all their professional activities. These exposures can derive, due to the effects of direct and scattered radiation, in deterministic effects (radiodermitis, aged skin, cataracts, telangiectasia in nasal region, vasocellular epitelioms, hands depilation) and/or stochastic ones (cancer incidence). A methodology has been proposed for estimating the radiation risk or detriment from a group of six exposed interventional radiologists of the Hospital Universitario La Fe (Valencia, Spain), which had developed general exposition symptoms attributable to deterministic effects of ionizing radiation. Equivalent doses have been periodically registered using TLD's and wrist dosimeters, H(p)(10) and H(p)(0.07), respectively, and estimated through the observation of translocations in lymphocytes of peripheral blood (biological methods), by extrapolating the yield of translocations to their respective dose-effect curves. The software RADRISK has been applied for estimating radiation risks in these occupational radiation exposures. This software is based on transport models from epidemiological studies of population exposed to external sources of ionizing radiation, such as Hiroshima and Nagasaki atomic bomb survivors [UNSCEAR, Sources and effects of ionizing radiation: 2006 report to the general assembly, with scientific annexes. New York: United Nations; 2006]. The minimum and maximum average excess ratio for skin cancer has been, using wrist physical doses, of [1.03x10(-3), 5.06x10(-2)], concluding that there is not an increased risk of skin cancer incidence. The minimum and maximum average excess ratio for leukemia has been, using TLD physical doses, of [7.84x10(-2), 3.36x10(-1)], and using biological doses, of [1.40x10(-1), 1.51], which is considerably higher than incidence rates, showing an excess radio-induced risk of leukemia in the group under study. Finally, the maximum radiological detriment in the group, evaluated as the total number of radio-induced cancers using physical dosimetry, has been of 2.18/1000 person-year (skin and leukemia), and using biological dosimetry of 9.20/1000 PY (leukemia). As a conclusion, this study has provided an assessment of the non-deterministic effects (rate of radio-induced cancer incidence) attributable to the group under study due to their professional activity.

Biological dosimetry in a group of radiologists by the analysis of dicentrics and translocations

The results of a cytogenetic study carried out in a group of nine radiologists are presented. Chromosome aberrations were detected by fluorescence plus Giemsa staining and fluorescence in situ hybridization. Dose estimates were obtained by extrapolating the yield of dicentrics and translocations to their respective dose-effect curves. In seven individuals, the 95% confidence limits of the doses estimated by dicentrics did not include 0 Gy. The 99 dicentrics observed in 17,626 cells gave a collective estimated dose of 115 mGy (95% confidence limits 73-171). For translocations, five individuals had estimated doses that were clearly higher than the total accumulated recorded dose. The 82 total apparently simple translocations observed in 9722 cells gave a collective estimated dose of 275 mGy (132-496). The mean genomic frequencies (x100 +/- SE) of complete and total apparently simple translocations observed in the group of radiologists (1.91 +/- 0.30 and 2.67 +/- 0.34, respectively) were significantly higher than those observed in a matched control group (0.53 +/- 0.10 and 0.87 +/- 0.13, P < 0.01 in both cases) and in another occupationally exposed matched group (0.79 +/- 0.12 and 1.14 +/-0.14, P < 0.03 and P < 0.01, respectively). The discrepancies observed between the physically recorded doses and the biologically estimated doses indicate that the radiologists did not always wear their dosimeters or that the dosimeters were not always in the radiation field.

Assessment by cytogenetic analysis of the radioprotection properties of propolis extract

Propolis obtained from honeybee hives has been used in folk medicine as an anti-inflammatory, anti-carcinogenic or immunomodulatory agent. In animal studies, the radioprotector effect of propolis has been attributed to its free-radical scavenging properties. The present study was carried out to show the protective properties of propolis extract against DNA damage induced by gamma irradiation. The evaluation of the radioprotective effect of propolis has been carried out by the analysis of chromosome aberration induction after several doses of gamma rays. The results of an analysis in the presence of ethanol extract of propolis (EEP) were compared with the dose-effect calibration curve for gamma-rays by analysis of chromosome aberrations without propolis, a decrease in the radiation-induced chromosome aberrations has been observed to be higher than 50% for all the doses.

Analysis of Translocations in Stable Cells and their Implications in Retrospective Biological Dosimetry

The aim of the present study was to evaluate the influence of the exclusion of cells with unstable aberrations in the elaboration of dose-effect curves for translocations and their implications in biological dosimetry of past exposures. To establish dose-effect curves, peripheral blood samples were irradiated with 60Co gamma rays at ten different doses and the yield of translocations analyzed by FISH was considered in all cells and in stable cells (those without dicentrics, acentrics or rings). To discriminate transmissible translocations, the dose- effect curve for total apparently simple translocations in stable cells was chosen as the reference. In stable cells, dose- effect curves for apparently simple translocations without pseudosimple and complex-derived one-way patterns, tAbtBa and total translocations were obtained. None of these curves differed from the reference curve. When all cells were considered, only the curve for total translocations was significantly different from the reference curve. From the results obtained it can be concluded that the use of dose-effect curves for apparently simple translocations in stable cells and in all cells will give similar dose estimates in retrospective biological dosimetry studies. However, the use of dose-effect curves for total translocations in all cells will lead to underestimations of the dose mainly at high doses.

Specific and total IgE in patients with recurrent, acute urticaria caused by Anisakis simplex

Titres of parasite-specific IgE were investigated in 19 patients thought to have recurrent, acute urticaria caused by sensitization to Anisakis simplex (Dujardin, 1845), before and after they were placed on a fish-free diet. Patients with other allergic disease and those being treated with corticosteroids or antihistaminics were excluded. Skin-prick tests were carried out with A. simplex extract, and blue- and white-fish extracts. The CAP system (Pharmacia), a commercial test kit developed for the assay of food-specific IgE, was used to monitor serum concentrations of total IgE and antigen-specific IgE against Anisakis, Ascaris, Echinococcus, Toxocara, tuna, salmon, shrimp, mussel and cod. Before going on a fish-free diet, the 19 patients had CAP scores against A. simplex of 5 (three cases), 3 (seven) or 2 (nine). After a mean of 120 days on the diet, the scores against A. simplex were unchanged in 15 of the cases, reduced in three [from 5 to 4 (one case) or from 2 to 0 (two cases)] and increased in one (from 2 to 3). Most (16) of the patients no longer had any urticaria and the others reported significant reductions in the intensity and frequency of their symptoms.

Recidivous acute urticaria caused by Anisakis simplex

This study aimed to determine the cause of acute recidivous urticaria in patients who usually eat fish or other seafood. Twenty-five patients were studied. The skin prick test with larval Anisakis simplex extract was performed; total and specific IgE against A. simplex was measured with the CAP System; specific antibodies to A. simplex were determined by ELISA; and immunorecognition patterns of the sera were studied by Western blot. Nineteen patients showed specific IgE to A. simplex, but specific IgE to Ascaris was demonstrated in only two patients. No patients reacted to Toxocara canis or Echinoccocus granulosus antigens with the same test. The skin prick test was positive in 16 patients, in two of them persisting for 48 h. Five patients showed neither skin reaction nor specific IgE to A. simplex. Sera showed specific immunoglobulin levels against A. simplex larval crude extract, by both ELISA and Western blot. Likewise, specific immunoglobulin levels against excretory-secretory antigen were also measured by ELISA. Only one patient showed sensitization to fish. A. simplex was found to be the main cause of acute recidivous urticaria in patients who usually eat fish and are not sensitized to it.

Clinical tolerance, parasitological efficacy and environmental effects of dehumidifiers in stable asthmatics sensitized to house dust mites

Dehumidifiers (DH) are potentially effective appliances as coadjuvant therapy in the treatment of bronchial asthma caused by sensitization to house dust mites. The aims of this study were to analyze DH tolerance in asthmatic patients, to assess the parasitological effects and to analyze the environmental effects produced by the use of these appliances in the bedrooms of asthmatic patients sensitized to house dust mites. 10 stable asthmatic patients sensitized to house dust mites were studied. DH appliances (CD-300) were installed in their bedrooms. Each patient was given symptom scoring tables and a portable peak expiratory flow (P.E.F.) during a period of 5 months, 1 month before installing the DH and 4 months afterwards. To study the parasitological efficacy of the DHs, we analyzed dust samples from the bedrooms and determined the Der p I, Der f I and Der II allergens by means of a modified ELISA based on monoclonal antibodies. Dust samples were collected before installing the DHs and after they had been working for 2 and 4 months. Dry temperature and relative humidity measurements at three time intervals (7-9, 15-17 and 22-24 h) were carried out. The 1st measurement was done prior to installation of the DHs in the patients' bedrooms and the 2nd and 3rd were achieved 2 and 4 months respectively after the installation. Statistical analysis was done by comparison of paired means. No significant differences were detected in the patients' symptoms nor in the P.E.F. measurements in the course of the study. Decreases in the house dust mite allergens were observed in 4 bedrooms. A significant decrease in relative humidity in the bedrooms of mite asthma patients after use of dehumidifier appliances was observed (p < 0.01). Significant differences between the measurements of the bedrooms with and without DH were detected (p < 0.01). In summary, DHs were well tolerated by stable asthmatic patients, produced a significant decrease in the relative humidity level and showed some parasitological efficacy.

Anaphylaxis induced by ingestion of a pollen compound

We report on the case of a 32-year-old atopic patient who showed a severe anaphylactic reaction due to the ingestion of a pollen compound prepared in an herbalist's. A few minutes after ingestion, generalized pruritus, difuse erythema, facial edema, cough, hoarseness and dysphonia appeared, and the emergency administration of subcutaneous epinephrine and intravenous methylprednisolone was necessary. Skin tests with a battery of inhalants and food allergens were performed. The patient only showed sensitization to Artemisia vulgaris, Taraxacum officinalis and Salix alba. Specific IgE levels were evaluated by FEIA-CAP giving a seric level of CAP class 3 to Artemisia vulgaris and class 2 to Taraxacum officinalis and Salix alba. Samples of the pollen compound were shown in the microscopical analysis to be 93% pollens and 6% fungi. In the qualitative study Taraxacum officinalis (15%), Artemisia vulgaris (5%) and Salix alba (15%) were the main elements identified. In summary, this case study describes a food-induced systemic reaction due to a pollen compound in an atopic patient with a history of allergic rhinitis. Pollinic patients must be informed on the risks that the consumption of these compounds might cause.

Seasonal variation in proliferative response and subpopulations of lymphocytes from mice housed in a constant environment

A seasonal variation in the proliferative response to mitogens and in the proportion of splenic lymphocyte subpopulations was found in mice housed in a constant environment. The lymphoproliferative responses to T-cell and B-cell mitogens reached maximum values in autumn and summer. Identification of lymphocyte subpopulations by flow cytometry demonstrated that the proportion of T cytotoxic-suppressor (Tcs) lymphocytes was significantly higher in autumn and summer than in spring and winter. However, the proportion of B lymphocytes was significantly lower in spring than in the other three seasons, whereas the proportions of T and T helper (Th) cells did not show any seasonal variation. On the other hand, we observed a significant correlation between the level of mitogenic responsiveness and the proportion of Tcs cells, but not between the former and the proportions of B, T or Th cells. These data suggest that the seasonal variation in murine lymphoproliferative responses may depend on the cyclic changes in the proportion of Tcs lymphocytes; these changes, in turn, may be predetermined by the inherent internal biological rhythms of the animal.

Analysis of DNA Content in Supraglottic Epidermoid Carcinoma

DNA analysis by flow cytometry is considered to be of prognostic value in epidermoid carcinoma of the head and neck. However, few and contradictory studies have been made on laryngeal carcinomas. We studied 48 epidermoid carcinomas in patients subjected to horizontal supraglottic laryngectomy with a 5-year- followup. The technique described by Hedley for fixated and paraffin-embedded tumors was used. Thirteen tumors were excluded on the grounds of presenting variation coefficients in excess of 10. Of the 35 cases analyzed, 28 (80%) were diploid and seven (20%) aneuploid. No correlation was observed between tumor ploldy and patient survival, recurrence, or any of the histopathological variables studied.

[An analysis of the DNA content in a stage-T-1 epidermoid carcinoma of the vocal cord. The methodology and results]

DNA content of tumor cells determined by flow cytometry has been correlated to biologic behavior and to prognosis for many solid tumors, but insufficient data has been accumulated for squamous cell carcinoma of the larynx. In order to know the predictive value of this parameter in the prognosis of T-1 vocal cord squamous cell carcinoma, we have studied 27 patients submitted to cordectomy. The patients outcome was followed for a minimum of five years or until death, DNA content was determined by Hedley method in paraffin-embedded sections of formalin-fixed blocks in an EPICS Profile flow cytometer. 24 of these tumors were diploid (89%) and 3 aneuploid (11%). We didn't find statistical correlation between ploidy and survival, local failure or someone of the pathological parameters.

Myocardial glutathione alterations in acute coronary occlusion in the dog

Glutathione (GSH) decreases in dog myocardium upon acute coronary occlusion when compared with sham-operated dogs. Total glutathione content (GSHeq = GSH + 2GSSG) remains unchanged throughout the experiment (6 h after surgery) in both sham- and acute coronary occlusion-operated dogs. GSSG and GSH/GSSG ratio increases and decreases respectively in all animals but tends to reach the normal value after 6 h in sham-operated dogs. Both parameters (GSSG and GSH/GSSG ratio) remain altered in acute coronary occlusion-operated ones. This alteration of glutathione status in ischemic myocardium is discussed.