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Biomedical subjects

D Vervloet

Publications and source records attributed to D Vervloet.

At least 109 records · Page 6Linked to original sources
PubMed1995

Indoor allergen levels in day nurseries.

BACKGROUND: Because allergic sensitization seems to occur especially during infancy, we decided to evaluate such an exposure in day nurseries. METHODS: Thirty day nurseries in Marseilles, which were selected at random, were visited during 2 weeks in April 1993. Routine cleaning includes daily cleaning of smooth floors, weekly laundering of sheets, and monthly cleaning of soft toys. Mattresses are encased in synthetic covers. Dust samples were collected from four settings: infants' mattresses and pillows, smooth floors, and soft toys. Levels of mite, cockroach, cat, and dog allergens were analyzed with a monoclonal antibody-based ELISA. RESULTS: Mite allergen levels were lower than the proposed threshold level for sensitization (2 micrograms/gm of dust) on 94% of mattresses and soft toys and on 100% of floors and pillows. Cat allergen levels in mattresses ranged from less than 0.1 to 4.5 micrograms/gm dust. On floors, cat allergen levels ranged from less than 0.1 to 2.4 micrograms/gm dust. Only 10% of pillows and soft toys had levels greater than 2 micrograms/gm of dust. Fel d I levels were significantly higher (p < 0.03) in mattresses from nurseries with curtains and were correlated with the percentage of children with a cat at home. In almost all day nurseries, cockroach allergen (Bla g I and Bla g II) levels were very low. Only three samples from mattresses had dog allergen levels greater than 2 micrograms of Can f I allergen per gram of dust. On floors the level was always lower than 2 micrograms/gm. CONCLUSIONS: These data clearly show that indoor allergen levels are much lower in day nurseries than in most houses. Most samples contain allergen levels below threshold levels for sensitization. Thus children of atopic parents are less likely to become sensitized to indoor allergens in day nurseries than in their own homes. In addition, this study emphasizes the efficacy of avoidance measures such as use of synthetic protective mattress covers, frequent washing of sheets and soft toys, and avoidance of carpets and curtains.

Allergens↗
PubMed1995

Evaluation of atopy through an expert system: description of the database.

BACKGROUND: In order to understand the medical decisions taken during the initial visit of a new asthmatic patient, a group of experts designed an expert system which provides conclusions about severity, precipitating factors and treatment. Rules for atopy and the assessment of allergic factors have been discussed and implemented in the expert system. Conclusions about severity have been yet validated using an appropriate methodology. OBJECTIVE: The aim of this study was to investigate a sample of 471 patients according to conclusions regarding atopy. METHODS: A total of 471 cases report forms (CRF) was filled in for adult asthmatic outpatients, seen for the first time in our clinic without emergency situations. Data of each CRF were used by the expert system to draw conclusions. The expert system discerns three patterns for atopy, yes, possible or no. The variables known to reflect different features according to the classification of asthma as atopic or not have been studied. The variables used in the rules for atopy, obviously linked to the conclusion, were not compared. For many medical problems no unique objective solution exists and this is why a group of patients with possible atopy was introduced. RESULTS: Patients with atopy had less severe asthma (P = 0.01), a better FEV1 value (P = 0.0007) and showed their first symptoms of asthma earlier (P = 0.00001) than patients without atopy. CONCLUSIONS: The characteristics of the group studied here are consistent with the literature. This could be considered as an indirect validation of the expert system. Moreover, patients with possible atopy show intermediate findings for these variables and it is possible to suggest a 'dose-effect' relationship.

Adolescent↗
PubMed1995

Is systematic preoperative screening for muscle relaxant and latex allergy advisable?

We investigated a female population prior to general anaesthesia, using skin prick tests with latex and muscle relaxants to appraise the validity and feasibility of a systematic preoperative screening for these substances. Anaesthetists performed skin tests, and positive and doubtful tests were checked in our allergy department. Of 114 patients, 42 had uninterpretable tests because of dermographism (28 patients) or suppression of skin reactivity (14 patients). Among the other 72, nine had a positive or doubtful test to latex, and seven a positive or doubtful test to one or more muscle relaxants. After checking, only four sensitizations to latex and one to muscle relaxant were confirmed. In conclusion, a systematic screening for latex and muscle relaxant allergy is not advisable. In contrast, screening for latex allergy in selected high-risk groups (spina bifida, health-care workers) is necessary.

Adult↗
PubMed1995

Housing and house-dust mites.

Because the mite-allergen content in homes is highly variable even in the same geographic area, we tried to determine which variables influence mite infestation. We evaluated mite-allergen content in bedding relative to housing conditions and living habits. This cross-sectional study included 108 homes. Housing conditions were assessed by an architect and living habits by a researcher specialized in social and family economics. Group I allergen level was measured on the mattress dust with monoclonal antibodies, and relative humidity (RH) was monitored in the bedroom during a 2-week period. Homes with low RH did have low mite-allergen content. In contrast, homes with intermediate RH levels had very variable mite-allergen content. Using analysis of variance and a logistic regression analysis, we were unable to identify any variable predictive of mite-allergen content. Thus, factors other than relative humidity seem to influence mite infestation. Moreover, the absence of association between mite infestation and ventilation rate might be accounted for by the gentle climate in our area with notable outdoor RH.

Allergens↗
PubMed1995

Assessment of the severity of asthma by an expert system. Description and evaluation.

Asthmaexpert, an expert system (ES), was produced at the special request of several clinicians in order to better understand the medical decisions made clinical experts in managing an asthmatic patient. We describe and evaluate this knowledge base, focusing mainly on assessment of the severity of asthma. After compiling data from a patient, Asthmaexpert assesses the severity of the disease and identifies the trigger factors involved, suggests any further investigations that may be required, and offers a treatment strategy. Implemented with Nexpert and Hypercard, it runs on a MacIntosh personal computer. The validation stage involved eight clinical experts who provided 20 case report forms (CRF) with their conclusions about management of asthma. The CRF were then programmed into the ES, which provided its own conclusions about the same subjects. Afterward, all the experts evaluated the conclusions given by ES or by their colleagues in a double-blind manner. One hundred twenty-seven CRF were available. The reliability of the experts' opinions was good, with a substantial consensus between them when assessing severity scores (kappa = 0.27 to 0.54). There was no difference in concordance of opinions on severity scores either between the experts who designed the system and ES or between the other experts and ES (weighted kappa = 0.72 and 0.69, respectively). Experts judged that the severity scores given by ES were as good as those proposed by their colleagues, and that the overall conclusions given by ES were as good as or better than those given by their colleagues. The conclusions drawn by ES were given a good rating.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

[Is atopy a risk factor of occupational asthma?].

General reviews about occupational asthma divide the susceptible allergens capable of initiating asthma into two distinct groups: those of high and of low molecular weight. Atopy would be a risk factor for developing occupational asthma to high molecular weight allergens but not to those of low molecular weight. In this work we have examined several studies and have analysed in a critical manner the relationship which exists between atopy and occupational asthma. The high molecular weight allergens studied were: snow crabs, laboratory animals, flour, proteolytic enzymes and psyllium. Those of low molecular weight were: red cedar, isocyanates, phthalic anhydride. Amongst allergens of high molecular weight there is a undeniable relationship between atopy and sensitisation to the allergen incriminated. However, the relation between atopy and asthma is more debatable except for baker's asthma. For more allergens of low molecular weight, atopy does not seem to favour the appearance of asthma, however, it may play a role in the occurrence of asthma to red cedar. The difference between the two groups of allergens is not as clear-cut as in the work that has appeared up until now and the exclusion of atopics from being hired would appear excessive.

Allergens↗
PubMed1995

House dust mite allergen content in two areas with large differences in relative humidity.

BACKGROUND: Striking differences in mite counts and mite-allergen levels have been documented between dwellings located at sea level and high altitude. Apart from relative humidity (RH), several other factors, ie, temperature, UV exposure, and altitude per se could account for this difference. OBJECTIVE: To evaluate whether RH by itself could influence mite infestation by comparing mite-allergens levels in two towns differing only with respect to RH. METHODS: We compared group I allergen content in two Moroccan towns: Casablanca, located on the seashore and Marrakech located at 1404 feet. Mean (+/- SD) RH in years 1990 and 1991 was 81.2 +/- 2.9% in Casablanca and 56.0 +/- 7.6% in Marrakech. Mean annual temperatures were 17.7 +/- 4.0 degrees C and 20.2 +/- 6.4 degrees C in Casablanca and Marrakech, respectively. In each town, 20 asymptomatic subjects agreed to participate in the study. Their mattresses were vacuum-cleaned for a standardized duration (2 min/m2). Mite allergen-content was evaluated using monoclonal antibodies and ELISA and results expressed as micrograms of group I (Der pI+Der f I) allergens per gram of dust (micrograms/g dust). RESULTS: Mean (+/- SD) group I allergen level was 8.3 +/- 8.8 micrograms/g in Casablanca and 0.6 +/- 0.6 micrograms/g dust in Marrakech, a difference that is highly significant (P = .001). In both areas, mean Der f I allergen level was low (0.7 +/- 0.5 and < 0.1 micrograms/g dust, in Casablanca and Marrakech, respectively). CONCLUSION: This study shows that house dust mite allergen content in households depends on RH rather than on temperature.

Allergens↗
PubMed1995

[AIDS: a model for the study of atopy?].

The drug intolerance and allergic manifestations linked to infection with the Human Immunodeficiency Virus (HIV) are often misunderstood. However, in the light of recent advances in immunopathology, these manifestations perhaps give an indication as to more general mechanisms of allergy. Drug intolerance is frequent during the course of AIDS, and is largely due to sulphamides; more rarely to pentamidine or amoxycillin associated with clavulanic acid. Other allergic manifestations are frequent in subjects suffering from AIDS, and occur all the more so in those subjects who are atopic before their immunodepression occurred. Metabolic anomalies occurring during the course of the disease perhaps partially explain certain aspects of drug intolerance. However, it seems that it is particularly the immunological changes which are at the origin of allergic manifestations to these diseases. AIDS is characterised by polyclonal activation of B-lymphocytes which leads to hyper-gammaglobulinaemia. This excess of antibody confronted with an excess of antigen in association with the administration of high doses of long-term antibiotics would favour the formation of antigen antibody complexes which may be responsible for the manifestations of a type of "serum sickness". Besides, there is a specific dysregulation of IgE synthesis as evident by a rise of serum IgE in subjects suffering from AIDS. That would explain the progressive increase in the expression of interleukine-4 and interleukine-10 during the course of the disease at the expense of the expression of interleukine-2 and interferon gamma. The shift from a Th1 cytokine secretion profile to that of a Th2 profile could be a consequence of decreased IL12 production by HIV infected monocyte/macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗
PubMed1995

[The relation between rhinitis and allergic asthma. The action of antihistaminics on bronchial hyperreactivity].

The connections which maintain rhinitis and allergic asthma are less simple than it appears. If there is an indisputable relationship between rhinitis and asthma it is far from systematic. Several factors regulate this relationship. The sensitivity towards perennial allergens is more readily associated with asthma or non-specific bronchial hyper-reactivity than the sensitisation to seasonal allergens while both are connected to rhinitis. Several explanations can be touched upon: the size of the allergen dose, the duration of exposure, and polysensitisation. On the other hand the risk of developing asthma is much greater if there is an increase in the total IgE level. Finally the intensity of nasal inflammation may itself alter the intensity of the bronchial hyperreactivity. In spite of these connections and the efficacy of the recent anti-histamines on rhinitis, the known effects of anti-histamines on the bronchi remain marginal.

Allergens↗
PubMed1994

[Asthma-allergy. Altitude: a study model].

Several epidemiological studies have now established the relationship between atopy and bronchial asthma. The study of the role of altitude in sensitization, bronchial reactivity, clinical symptoms and allergen exposure in asthma is a good model for understanding the disease. It is now demonstrated that in altitude there is a major decrease in the number of mites (one of the major aeroallergens) and a low mite antigenic load (measured with monoclonal antibodies). In altitude, the climatic factor which has by far the greatest effect on the development of mites is indoor relative humidity which is much lower that at sea level. These findings explain the clinical improvement of some asthmatic patients and help understand the association between the presence of indoor allergens and asthma.

Allergens↗
PubMed1994

Effects of castration and testosterone on Fel dI production by sebaceous glands of male cats: I--Immunological assessment.

Fel dI is produced by salivary and sebaceous glands. Hormonal control of sebum production is clearly established. The influence of cat castration and supplementary treatment with testosterone on the production of sebum and Fel dI in cat skin have been researched in this study. On day 1, 12 male cats were anaesthetized and three skin areas carefully shaven. Then the level of lipids on skin surface was measured by means of a photometric method. Finally, the three areas of skin were washed with 5ml of distilled water through a plastic cylinder. Fel dI collected in the washes was measured with a two-site monoclonal antibody based ELISA. On day 2, six cats were castrated, the other six were used as a control group. Two and 4 weeks later, the levels of lipids and Fel dI in skin washes were measured again in all cats. On day 30, the six castrated cats were injected intramuscularly with prolonged-action testosterone. Two weeks later, quantification of lipids and Fel dI in all animals was repeated. Sebum and Fel dI levels decreased in all castrated animals. Injecting the castrated cats with testosterone led to a significant increase in sebum and Fel dI production. Our findings indicate that Fel dI production is influenced by the production of hormones.

Allergens↗
PubMed1994

Effects of castration and testosterone on Fel dI production by sebaceous glands of male cats: II--Morphometric assessment.

A morphometric study of cat sebaceous glands was performed to evaluate the effects of castration and testosterone treatments. Skin biopsies were taken in six cats before castration, after castration and after the testosterone injections administered after castration (total number of biopsies: 18). Ninety 8 microns thick sections of each biopsy were assessed for image analysis processing (SAMBA 2005, ALCATEL TITN). The variations in glands and cells size were evaluated on digitized microscopic images by morphometric parameters included in the SAMBA software package. An original software was developed for the analysis of the spacial gland structure. The best morphometric parameters were selected in a first step of the study, and included the nuclear surface (NS), the cell surface (CS) and the nuclear/cellular surface ratio (N/C). These three parameters were then compared in each group of samples for the six cats. It was shown that after castration the N/C (21%) significantly increased compared with prior to castration (12.6%). This 59.8% increase was mainly due to cell cytoplasm shrinking reflecting a decrease of the cell activity. The testosterone administered after castration produced a reverse effect with a N/C ratio back to normal (11.4%) and a significant cell cytoplasm and gland enlargement as shown by the three dimension constructions. This morphometric data correlated with the measurement of sebum and Fel dI productions. The negative effects of castration and the positive effects of testosterone on the sebaceous cells and glands volume favour the hypothesis that cat sebaceous cells are subject to hormonal control this is also likely to apply to the Fel dI production.

Allergens↗