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Biomedical subjects

B Guérin

Publications and source records attributed to B Guérin.

At least 91 records · Page 5Linked to original sources
PubMed1987

Double-blind, placebo-controlled immunotherapy with mixed grass-pollen allergoids. I. Rush immunotherapy with allergoids and standardized orchard grass-pollen extract.

Forty-five grass pollen-allergic patients were randomly assigned to three groups according to their skin test and RAST sensitivities and the severity of seasonal rhinitis. Eleven patients were treated with placebo (group 1), 19 patients (group 2) were treated with a six-mixed grass-pollen allergoid prepared by mild formalinization with a two-step procedure, and 15 other patients were treated with a standardized orchard grass-pollen extract (group 3). Because of a different immunotherapy schedule, only patients placed in groups 1 and 2 received the extracts in a double-blind fashion. Rush immunotherapy was performed in 3 to 6 days, and the maintenance dose was subsequently administered weekly for 4 weeks and every 2 weeks until the end of the grass-pollen season. During the season, a coseasonal treatment was administered. Systemic reactions occurred during the rush protocol in 36.8% of patients treated with allergoid and 20% of patients who received the standardized extract. Only patients treated with allergoid had systemic reactions during maintenance dose. The reactions observed with the standardized extract were more severe. Total doses of allergoid ranged from 2350 to 13,500 protein nitrogen units. Symptoms and medication scores during the peak of the season were analyzed. Patients treated with the standardized allergen had a significant reduction of the number of days of symptoms during the month of June (9.5 +/- 6.7 days; p less than 0.005) and of medication scores (1.3 +/- 1.4; p less than 0.01) compared to patients receiving placebo (19.4 +/- 8.1 days; medication score, 2.8 +/- 2.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1986

Effect of infection of the genital tract on the concentration of IgG and albumin in bull serum and semen.

Bovine IgG and albumin concentrations were determined from serum and semen of 59 bulls that were divided into 4 groups: 35 non-infected bulls (Group 1); 10 with vesiculitis due to Corynebacterium pyogenes (Group 2); 10 bulls with orchitis due to Chlamydia psittaci (Group 3); and 4 bulls with infectious vesiculitis (Group 4) sampled both before and after antibiotic treatment. Serum IgG concentrations (25 mg/ml approximately) were similar in non-infected (Gp 1) and infected bulls (Gp 2,3,4) whereas serum albumin concentrations were greater in infected than in non-infected bulls (51 mg/ml vs.41 mg/ml; p less than 0.01). By contrast, both semen IgG and albumin concentrations in infected bulls (0.47 and 0.54 mg/ml respectively) were significantly different from those of non-infected bulls (0.14 and 0.32 mg/ml; p less than 0.01). In addition, bulls with chlamydial orchitis had both semen (but not serum) IgG and albumin levels higher than those suffering from vesiculitis (p less than 0.01). Antibiotic therapy led to recovery and simultaneously to decreased concentrations of semen IgG and albumin. These results strongly suggest a local IgG synthesis or selective diffusion after such genital infections and further indicate that semen IgG and albumin assays could be a new and valuable tool for diagnosis and evaluation of genital infections.

Animals↗
PubMed1986

Deficiency of uncoupler-stimulated adenosine triphosphatase activity in yeast mitochondria.

Oligomycin-sensitive ATPase activity was studied in isolated yeast mitochondria. The protonophore CCCP, at a concentration which completely inhibited ATP synthesis, induced only a low rate of hydrolysis of externally added ATP, and the extent of hydrolysis was dependent upon phosphate (Pi) concentration. CCCP promoted hydrolysis of intramitochondrial ATP. However, hydrolysis of externally added ATP was total in a medium containing potassium phosphate plus valinomycin. Without ionophores, ATPase activity was only observed at high external pH or with detergent-treated mitochondria. Under state 4 conditions, external ATP had access to the catalytic nucleotide site of ATPase as shown by 32Pi-ATP exchange experiments. These results are discussed in terms of a limitation of the translocase-mediated ATP/ADP exchange in uncoupled mitochondria.

Adenine Nucleotides↗
PubMed1986

Allergy in the Mediterranean area. II: Cross-allergenicity among Urticaceae pollens (Parietaria and Urtica).

Pollens of related species usually share common antigens and are cross-reacting but this is not always the case. The cross-allergenicity of two species of Urticaceae pollens (Parietaria and Urtica, nettle) was sought by means of RAST-inhibition and isoelectric focusing. A preliminary experiment in forty-two patients investigated by means of skin tests and RAST showed that most patients were either allergic to Parietaria or nettle and that both reactivities were uncommonly associated. The results of RAST-inhibition confirmed the total absence of cross-reactivity between these two related species. IEF patterns indicated that most proteins are in the acidic range of pH and did not reveal large discrepancies. Parietaria and Urtica pollens, although belonging to the same family and having close microscopic patterns, have very different allergenic activities. This study demonstrates that cross-allergenicity cannot be predicted.

Adolescent↗
PubMed1986

[Critical study of an interdisciplinary survey of urinary schistosomiasis in Burkina Faso].

We consider an approach to built on a score summarizing some demographic, social, geographic and parasitologic data for purpose of measuring the health impact of schistosomiasis. Operational definitions are given for the social, ecological and medical variables and for the survey design. Twenty villages from the Bam-Kongoussi district were kept for the survey, giving a sample of 11,396 peoples. The process of the survey is described. The overall response rate is 63%. The sensitivity of the survey's results in regard to the non-responses is considered along with the possibility to implement a call back survey.

Adolescent↗
PubMed1985

[Atopy screening: prick multitest, total IgE or RAST? On the value of allergologic testing of the staff of an industrial bakery].

The predictive value of diagnostic tests for the recognition and differentiation of allergic diseases of the immediate type has been evaluated on the basis of the results of a non-selective allergologic-pneumologic examination of the staff of an industrial bakery. Out of the 314 subjects tested, 22 (7%) had a respiratory allergy against flour (flour rhinitis and/or flour asthma), and 21 (6.7%) a preexistent atopic disease without actual symptoms of flour allergy. Thus the predominance of atopy in the group examined was 13.7%. A prick-multitest was carried out in all 314 subjects on each forearm and allowed simultaneous and easy application of twice eight test substances ("atopy-screening" and "bakery-line"). 50% of the bakers with flour allergy also showed positive skin tests with non-occupational inhalative allergens (housedust, housedust mite, pollen) while only 9.2% of the subjects without respiratory allergy to flour did so. 17.1% of the heavily exposed, asymptomatic bakers showed a positive immediate reaction to the highly sensitive intracutaneous test with wheat flour. Here the problem of latent sensitization arises. With histamine the prick-multitest resulted - compared to the intracutaneous test - in 1.6% "false negative" and 3.2% only questionably positive results. Furthermore, 6.1% of the subjects showed a strong, and 3.2% a very strong, nonspecific reaction to the control solution glycerin. Despite these restrictions the prick-multitest proved far superior to measurement of total serum IgE for screening of atopy. Technical improvements have been made in the meantime by the manufacturer. Specific IgE was detected in RAST screening in 59 of the 306 subjects who underwent blood tests. The geometric mean of total IgE values was only 75 U/ml, and for the RAST-negative subjects 23.3 U/ml, while their 95% confidence level was 225 U/ml. This logarithmic-normal distribution of the measured values, together with the excessive normal-atopic overlap, makes it impossible to lay the test cutoff point in a way which results in an acceptable relation between sensitivity and specificity. For the population examined the sensitivity of the total IgE measurement was already below 50% at a cutoff point of 80 U/ml, while the positive predictive value did not yet reach 50% at 160 U/ml. This diagnostic test is at present certainly used too often and without sufficient awareness of its very limited predictive value. As a screening method the RAST is too expensive. Furthermore, the problem of a latent sensitization also exists for the RAST.

Adolescent↗
PubMed1985

Immunotherapy with a standardized Dermatophagoides pteronyssinus extract. I. In vivo and in vitro parameters after a short course of treatment.

Dermatophagoides pteronyssinus (Dp) is the major allergen in allergic asthma in France. Standardized and lyophilized Dp extracts are available, and their effectiveness after a short course of rush immunotherapy was examined in a placebo-controlled, double-blind study. Twenty patients received the Dp standardized extract, and 10 other patients received a placebo extract. Before and 7 weeks after rush immunotherapy, in vivo and in vitro parameters were examined. Bronchial provocation tests performed in a standardized manner demonstrated that a provocative dose causing a 20% fall in FEV1, a 25% fall in maximum mild expiratory flow rate, a 25% fall in maximum flow when 50% of the forced vital capacity has been expired, and a 35% fall in specific airway conductance were significantly (p less than 0.005 to p less than 0.01, Wilcoxon W test) improved in the treated group and remained unchanged in the placebo group. Skin test titration demonstrated that patients placed in the treated group had a significant (p less than 0.001, Wilcoxon W test) decrease of both end point titer and size of the largest wheal. No significant difference was observed in the placebo group. Serum Dp-IgE did not vary significantly in either group. Serum Dp antigen P1-IgG was significantly (p less than 0.001, Wilcoxon W test) increased in the treated group and slightly increased in the placebo-treated group. This study demonstrated that a Dp standardized extract administered by a rush protocol elicits a rapid and significant immune response and leads to a significant protection of the patients.

Adult↗
PubMed1985

Allergy in the Mediterranean area. III: Cross reactivity among Oleaceae pollens.

Pollens of closely related species often share common antigens and allergens although this is not always the case. Four species of Oleaceae pollens commonly found in the Mediterranean area were investigated for cross-reactivity: olive (Olea europaea), ash (Fraxinus exselsior), privet (Ligustrum vulgare) and Phillyrea angustifolia, a common bush. Twenty individual sera of patients allergic to Oleaceae were investigated for specific IgE antibodies against the four species of Oleaceae pollens. The results indicated a high degree of correlation between RAST titres of Oleaceae pollens but three gave a particular emphasis on one species only. Cross-reactivity among these four pollen species was sought by means of RAST inhibition, iso-electric focusing and tandem cross-immunoelectrophoresis. All tests revealed a high degree of cross reactivity although there is no total identity among these four pollen species.

Cross Reactions↗
PubMed1984

Comparative study on cat allergens from fur and saliva.

The allergenic components of cat fur extract were localized in the molecular weight range 65,000-40,000 and had a pI of 3.9-5, except one with a more acid pI of 3.5. The fraction with a mean molecular weight of 65,000 contained proteins of pI 4.5-5 and mainly cat serum albumin. The fraction with a mean molecular weight of 40,000 showed two peaks of activity. One of them was associated with a protein of pI 3.5, and immunodiffusion analysis showed the presence of 'Cat Allergen One'. A comparative study on cat saliva showed that the allergenic activity was restricted to proteins of the same molecular weight range. 'Cat Allergen One' was present in the fraction of molecular weight 40,000.

Allergens↗
PubMed1982

[Isolation of plasma membranes from murine peritoneal macrophages and production of a heterologous immune serum].

Plasma membranes of murine peritoneal macrophages were obtained after light pounding of the cells by differential centrifugation. Subcellular fractions were monitored by specific enzymatic assays and by electron microscopy. Injection of plasma membranes into the rabbit produced an anti-serum containing specific antibodies of macrophage membrane antigen detected by indirect immunofluorescence method.

Animals↗
PubMed1980

[Influences of acoustic coupling between source and vocal tract of the Fo of oral vowels. Consequence for the study of intrinsic characteristics].

With the aid of a two-mass model of the vocal source loaded by the input impedance of the vocal tract, we first study theoretically, then by simulation, the effects of source-vocal tract coupling on the intrinsic frequencies Fo of the French oral vowels. We explain the correlation which exists between Fo and the frequency of the first formant as well as the results from the experiment described by Ishizaka and Flanagan [1972]. In conclusion, we show that the acoustic coupling cannot explain the different values of Fo, intrinsic in the vowels, but on the contrary, a physiological coupling has to compensate for the effects of acoustic coupling to explain the characteristics revealed in natural speech.

Humans↗
PubMed1979

[Vasogenic cerebral oedema. Changes in membrane ATPases. Correction by a phospholipid precursor (author's transl)].

In vasogenic cerebral oedema, there is progressive quantitative and qualitative impairment of mitochondrial ATPase and of Na/K/ATPase. This impairment, which reflects the intracellular component of cerebral oedema, would appear to be related to changes in the phospholipid environment of the cell membrane enzymes. CDP choline, a metabolic phospholipid precursor, is to a certain extent capable of correcting this disturbed activity and at the same time reduce oedema.

Adenosine Triphosphatases↗
PubMed1977

Influence of adenine nucleotides on oligomycin inhibition of energy-transducing reactions in intact rat-liver mitochondria.

The inhibitory effect of oligomycin was investigated in intact mitochondria through oxidative phosphorylation and uncoupler induced ATPase activity. Results show that oligomycin inhibition curves can be either sigmoidal or hyperbolic depending on experimental conditions and chiefly on the metabolic state of mitochondria with regard to the distribution of mitochondrial endogenous adenine-nucleotides. Active respiration and uncoupler-induced ATPse activity produce sigmoidal titration curves for a high initial ATP : ADP ratio and hyperbolic curves for a low ATP : ADP ratio. Time-dependent inhibitions are observed for the two reactions. The maximal inhibitory action for low concentrations of the inhibitor is delayed by the initial presence of ATP or the possibility of generating from inorganic phosphate before adding oligomycin. Results presented here show that the initial adenine-nucleotide distribution is important for oligomycin sensitivity of energy-linked reactions. Although a limited conformational change of the oligomycin-sensitivity to the inhibitor, it is more likely that a gross structural change of the inner membrane induced by adenine-nucleotides modifies membrane permeability to oligomycin.

Adenosine Diphosphate↗
PubMed1976

[Permeability of yeast mitochondrial internal membrane: structure-activity relationship].

In order to investigate the possible relations between the anionic permeability and the functions (or the structure ) of the inner mitochondrial membrane, three types of organelles isolated from S. cerevisiae were tested: mitochondria (aerobic culture), promitochondria (anaerobic culture) and CAP-mitochondria (aerobic culture with chloramphenicol added). By using the technique of swelling in isoosmotic potassium salts, after a derermination of the isotonic conditions, it was possible to discriminate between an electrogenic (valinomycin induced) or an electroneutral (both valinomycin and uncoupler induced) translocation. 1) Mitochondria: The permeability properties of mitochondria are energy dependent: a) Respiring mitochondria are permeable to Cl-; Mg2+, however, inhibits this translocation. Phosphate transport seems to be exclusively electrogenic and mersalyl sensitive, but swelling inhibition by that thiol reagent is restored by Mg2+. b) Non respiring mitochondria are impermeable to Cl-, but ATP addition restores the permeability. Thiocyanate permeates as the anionic form and acetate as the undissociated form. The phosphate transport, sensitive to mersalyl, seems to be partially electrogenic. 2) Promitochondria: Deficient of respiratory enzymes but containing an oligomycin sensitive ATPase, they are impermeable to Cl- only when Mg2+ is added. In these conditions, an electrogenic phosphate transport, sensitive to mersalyl, is observed. 3) CAP-mitochondria: Although CAP-mitochondria are cytochrome deficient and contain an oligomycin insensitive ATPase, they are also impermeable to Cl- in presence of Mg2+. As in fully differenciated mitochondria, an electroneutral phosphate entry is observed; Mg2+ is required for mersalyl sensitivity.

Adenosine Triphosphatases↗