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Biomedical subjects

D Vervloet

Publications and source records attributed to D Vervloet.

At least 199 records · Page 11Linked to original sources
PubMed1987

Different bronchoconstrictor effects of carbachol boluses inhaled near residual volume or total lung capacity.

The purpose of this study was to determine if the lung volume at which aerosol inhalation begins (LVi) influences airway responses to bronchoconstrictor agents. We compared the effects of carbachol boluses (25, 50 and 100 ml), inhaled at high and low LVi (averaging 72.2 and 15.8% of vital capacity, respectively) on specific airway resistance (SRaw). In order to eliminate the possible influence of airway obstruction on aerosol distribution and deposition, we selected 5 asthmatic subjects with normal respiratory function (spirometry, SRaw, nitrogen washout and closing volume); furthermore, non-cumulative dose-response curves were obtained (i.e. the patients inhaled only one dose of carbachol on a given test day). Inhaling carbachol at low LVi yielded a significantly (p less than 0.01) larger degree of bronchoconstriction. Differences in bronchial responses were probably due to differences in the amount of particles deposited in the airways and/or to their distribution. These data suggest that LVi should be controlled for quantified inhalation provocation tests.

Adult↗
PubMed1987

[Immediate allergy,terrain and allergens].

Different backgrounds may be involved in the elicitation of IgE-dependent reactions; an atopic background, i.e. synthesis of specific IgE against common allergens and an allergic background, in the field of drug allergy and allergy to hymenoptera stings, in which atopy is probably not an important risk factor. Allergens have three-dimensional molecular configurations and this is an important determinant of their immunological reactivity. Only multivalent allergens can induce a specific release of mediators.

Allergens↗
PubMed1987

Asthma without airway hyperresponsiveness to carbachol.

Generally, asthma is closely associated with hyperresponsiveness to bronchoconstrictor agents. However, we have observed three patients who initially had symptoms of asthma but no hyperresponsiveness. Responsiveness to carbachol was assessed by specific airway resistance (SRaw) measurement after bronchodilatators had been discontinued. The carbachol challenge was repeated 6-18 months later. Initially, no change in SRaw was observed after inhalation of 3 mg carbachol (cumulated dose). On the second occasion, carbachol responsiveness increased into the asthmatic range while the baseline values of SRaw were not different. Since we have used the SRaw measurement, the bronchodilatator effect of maximal inspiration is not the explanation for the failure to demonstrate hyperresponsiveness. These observations suggest that airway hyperresponsiveness is not a necessary condition for induction of asthma and symptoms of asthma may precede the appearance of airway hyperresponsiveness.

Adolescent↗
PubMed1987

[Pulmonary localization of Kaposi's sarcoma].

The authors describe a case of a 61 year old man suffering from Kaposi's sarcoma with pulmonary involvement associated with a hairy cell leukaemia. The numerous associations with Kaposi's sarcoma are reviewed and the circumstances of the unexpected appearance of this disease, placing it in the group of opportunistic diseases. The prognosis is totally different according to whether it is an isolated Kaposi's sarcoma without visceral localisation or to a form with polyvisceral involvement and associated with another neoplasm or immunodepression.

Humans↗
PubMed1986

Appearance of specific antibody-bearing cells in human bronchial mucosa after local immunization with bacterial vaccine.

The immune response to local in vivo inhalation of a lysed bacteria vaccine was assessed in surgical specimens of main-stem bronchi from patients who had undergone pneumectomy for cancer. The patient population included 22 subjects; 11 of these received the aerosol vaccine twice a day for 10 days prior to surgery, while the remaining 11 patients were used as controls and were not immunized. The submucous glands of immunized subjects showed significantly more cells than did those of the controls, i.e., 62 +/- 8 versus 37 +/- 7, respectively (P less than 0.05). The following five antigens were chosen for study by fluorescence assay: Streptococcus pneumoniae types II and III, Haemophilus influenzae, Streptococcus sp. strain D19, and Klebsiella pneumoniae. An immunization-dependent correlation was found between immunoglobulin A, immunoglobulin A-bearing cells, and specific antibody-bearing cells on the one hand and three of the five antigens (S. pneumoniae types II and III and Streptococcus sp. strain D19) on the other hand. This is the first time that a relationship has been established between bacterial immunization of the lower respiratory tract and local immunoglobulin production in humans.

Adolescent↗
PubMed1986

[Comparative study of anticholinergic and betamimetic agents in the treatment of asthma attacks].

Four regimens of bronchodilatation therapy administered on 2 consecutive days were tested in 4 randomly selected groups of 6 asthmatic patients: 1) intravenous atropine + inhaled oxitropium bromide; 2) intravenous atropine alone; 3) intravenous salbutamol + inhaled salbutamol; 4) intravenous salbutamol alone. On the second day the treatments were crossed over, i.e. the groups which had received the intravenous + inhaled treatment on the first day received the same drug in i.v. form alone and vice versa. The intravenous doses of atropine and salbutamol were 0.5 mg each administered over 1 hour, and those of oxitropium and salbutamol aerosol were 100 mcg hourly for 6 hours. In addition, all patients received methylprednisolone 20 mg i.v. on each day of the study. Peak expiratory flow rate (PEFR), heart rate (HR) and arterial pressure were recorded before treatment, then hourly for 6 hours. All 4 regimes produced significant improvement in PEFR (P less than 0.01). Bronchodilatation was not significantly different in the 4 groups, but improvement was markedly better when intravenous injections were associated with inhalations. No side-effects were recorded with the anticholinergic drugs, whereas a slight but significant increase in HR (P less than 0.05) was observed with the adrenergic drug. This study suggests that anticholinergic agents provide a therapeutic alternative for severe acute asthma when beta 2-adrenergic stimulants cannot be used.

Administration, Inhalation↗
PubMed1986

[Results of specific desensitization in allergic asthma].

Some recent works currently give some solid scientific basis to suppose that immunization with appropriate antigens might be beneficial for asthmatic patients. As numerous studies have now shown on the one hand that there was a relation between allergy, inflammation and bronchial hyper-reactivity and in the other that desensitization was able to modify the liberation of mediators to inflammation and the responses attributed to these mediators. The number of controlled studies performed up till now with the principal allergens are, for asthma, insufficient. However, no-one currently doubts the efficacy of specific desensitization to spasmodic pollen coryza. For pollen asthma, six studies conclude that there were superior results with desensitization than to placebo. Two studies showed no difference. Four controlled studies made for episodic house dust mite coryza ended with a favourable result. In allergic bronchial asthma to the dust mite, nine studies were favourable and five showed no benefit. It should be mentioned at this stage that all the studies on children have shown favourable results. There are few studies on the efficacy of desensitization to animal squamae (epithelial debris). Nevertheless, a very recently published study has shown, using cat squamae, clinical efficacy on bronchial, nasal and ocular symptoms. Desensitization with mould extracts cannot be judged at present, published controlled studies on the subject are almost nonexistent. On the other hand at the moment one can say that with microbial antigens non-standardised antigens, no clinical evidence has been shown to date. Incidents and accidents encountered during specific desensitization in respiratory allergy are extremely rare but may be serious.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1986

[A national survey: the respiratory specialist and allergology].

In June 1984 we wrote to all 1,594 Registered French Respiratory Specialists in the medical directory, with a questionnaire to determine their diagnostic and therapeutic activity in the field of allergy. In September 1984 a second letter with the same questionnaire was sent to these Physicians who had not replied to the first. Finally in October 1984 a random sample of 21 Physicians who had not replied to the two letters were contacted by telephone. Among the 1,594 letters initially, 232 were to people not involved in the field of inquiry (Deceased doctors, those retired or not thoracic Physicians) or had not reached the address. After excluding this group, the level of response was established at 74% for the first delivery and 33% for second or 84% overall. Among 1,114 respondents overall, 79% admitted to activity in allergy varying from 55% in the Paris Region to a maximum of 92% in the South-East. The differences were less pronounced when the age of the physicians was allowed for. The most used diagnostic means are skin tests (90%), total IgE (68.6%) and specific IgE (57%) far ahead of non-specific bronchial provocation tests (20%) and specific tests (14.6%). Two hundred and sixty thoracic Physicians had no activity in the field of allergy.

Adult↗
PubMed1985

[Immediate hypersensitivity to quinine].

Systemic anaphylactic reaction with shock was observed after ingestion of an antipyretic combination product containing quinine. That quinine was responsible for the reaction was proven by immediate skin tests and by oral challenge tests. The demonstration of specific IgE's by a radioallergosorbent test (RAST) provided evidence for an immediate hypersensitivity mechanism.

Adult↗
PubMed1985

Leukocyte histamine release to suxamethonium in patients with adverse reactions to muscle relaxants.

In an earlier study we confirmed the usefulness of intradermal skin tests and histamine release in diagnosis of patients reactive to muscle relaxants, and we suggested an IgE-mediated reaction rather than an idiosyncratic mechanism. In a later study, we studied the relationship between (Formula: see text) that is one of the muscle relaxants producing the most frequent adverse reactions under anesthesia. Histamine release was measured in five patients with increasing concentrations of suxamethonium in the presence or absence of human serum albumin in Tris buffer. Suxamethonium by itself without any carrier in the buffer could, in vitro, act as a true allergen on target leukocytes in the sensitized patients' group. Acetylcholine (20 and 200 micrograms/ml) did not induce significant histamine release in five patients with positive histamine release in the presence of suxamethonium. Preincubation of leukocytes from 11 patients for 30 min with 20 and 200 micrograms of acetylcholine in Tris albumin CA++ Mg++ buffer decreased the histamine release induced by suxamethonium (10 micrograms/ml); mean maximal histamine release of 46% +/- 4.2 was reduced to 31.4 +/- 5.8 and 7% +/- 4 (p less than 0.001), respectively. However, in eight control subjects similar concentrations of acetylcholine did not change the maximal histamine release induced by anti-IgE (0.2 micrograms/ml). In the same way acetylcholine did not modify histamine release induced by Dermatophagoides pteronyssinus extract (1/10,000 w/v) in six patients allergic to this allergen. This study suggests that suxamethonium acts as a true allergen and that acetylcholine or one of its metabolites may act as a hapten inhibitor in the model of histamine release induced by suxamethonium.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1985

Anaphylactic reactions to suxamethonium prevention of mediator release by choline.

IgE antibodies cross-reacting with choline and suxamethonium were found in the sera of 15 of 22 patients with life-threatening sensitivity to suxamethonium, one of the most commonly used muscle relaxants. Furthermore, choline that is one of the metabolites of acetylcholine and a monovalent part of the suxamethonium molecule could act as a hapten inhibitor in vitro and in vivo, blocking specifically the basophil histamine release induced by suxamethonium and the positive skin tests to the drug in allergic patients. These results confirm the IgE dependency of allergic reactions to suxamethonium and suggest a possible way of preventing such reactions with choline.

Anaphylaxis↗