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Biomedical subjects

B Guerin

Publications and source records attributed to B Guerin.

At least 55 records · Page 3Linked to original sources
PubMed1985

The role of adenine nucleotide translocation in the energization of the inner membrane of mitochondria isolated from rho + and rho degree strains of Saccharomyces cerevisiae.

The energization of rho + and rho degrees isolated mitochondria was measured using a tetraphenylphosphonium selective electrode. In both strains translocase mediated ATP/ADP exchange energization was observed. This energization was more sensitive to uncoupler than that induced by respiration in rho + mitochondria. This observation is in accordance with the hypersensitivity of rho - cell growth to uncoupler.

Adenine Nucleotides↗
PubMed1985

Changes of the striatal 3H-spiperone binding 3-6 weeks after nigrostriatal denervation and after two years.

A complete unilateral lesion of the nigrostriatal pathway by 6-hydroxydopamine injection in the substantia nigra induced a drastic increase in striatal dopaminergic binding sites labelled by 3H-spiperone, 30 days after the lesion. This increase (75% over controls) was time restricted: it was only 39% and 34% over control values at respectively 25 and 35 days after the lesion. Furthermore, 45 days after the destruction of the substantia nigra, the density of labelled sites returned close to the homolateral control values, but remained higher than the contralateral ones, according to the right-left difference found in control animals. Quite later (2 years after the lesion), there was a decrease in the density of labelled sites as compared to the respective homolateral control levels. However, such binding sites tend to remain higher in the striatum of the lesioned side than in the striatum of the intact one, although such a difference was not statistically significant, being very close to the right-left asymmetry observed in control animals. Contrary to our previous results with 3H-Haloperidol, the apparent dissociation constant did not vary significantly, whatever the considered delay after the lesion. These results are discussed in the light of previous results obtained by others and by us.

Animals↗
PubMed1985

Comparison of the stability of a mite and a pollen extract stored in normal conditions of use.

Pollen extracts are stable in solutions containing 50% glycerol. The stability of Dermatophagoides pteronyssinus (Dp) extracts have not been determined. Two lyophilised extracts (Dp and cocksfoot pollen) were reconstituted in 50% glycerol and stored for up to 6 months at +4 degrees C. Every day the extracts were placed at room temperature for 1 hr to mimic the natural use of allergen extracts by allergists. Every 2 months the extracts initially prepared were compared to freshly reconstituted extracts by means of prick skin tests in fifteen allergic patients. It was observed that cocksfoot pollen extract is stable but there appears a slight but significant (P less than 0.05) decay in activity when the extract stored for up to 6 months was compared with a freshly prepared extract. On the other hand there is a significant (P less than 0.01) decay in activity of the Dp extract after 2 months of storage. Dermatophagoides pteronyssinus and cocksfoot pollen extracts behave differently when stored. These findings have particular importance in the diagnosis and treatment of allergic disorders.

Allergens↗
PubMed1985

Cross-allergenicity between extracts of hair from different dog breeds and cat fur.

Skin tests and RAST determinations with breed-specific dog allergen extracts and a cat allergen preparation were made on forty-four atopic patients divided into three groups. Group 1 were twenty dog-owning atopic patients without clinical signs of dog sensitivity, Group 2 contained twenty-one patients with a clinical history that suggested allergy to dogs, and Group 3 contained ten atopic patients who were sensitive to cats. In neither the in vivo nor the in vitro tests was there any evidence for dog breed specificity, nor was dog albumin found to be a major allergen in the population studied, though a few individuals showed strong RAST activity to albumin. Furthermore, a cat fur extract inhibited the reaction between dog hair and anti-dog serum, and a dog hair extract inhibited the reaction between cat fur extract and anti-cat serum.

Allergens↗
PubMed1985

Comparison between rush immunotherapy with a standardized allergen and an alum adjuved pyridine extracted material in grass pollen allergy.

Rush immunotherapy with a standardized and lyophilized cocksfoot pollen extract was performed in twenty-three allergic subjects and compared with classical immunotherapy done with an alum adjuved, pyridine extracted cocksfoot pollen extract (fifteen subjects) and a control group of ten patients. The three groups were perfectly matched. Clinical benefits were analysed by means of symptom scores. It was shown that rush immunotherapy gave significantly better results when asthma or rhinitis was considered than either classical immunotherapy (P less than 0.02) or in the control group (P less than 0.01 and 0.02). Skin tests were significantly reduced after rush immunotherapy and did not change in the two other groups. After the pollen season the skin test reactivity was increased in the rush immunotherapy group. Cocksfoot pollen specific IgE did not vary significantly in the three groups. Cocksfoot pollen specific IgG was significantly (P less than 0.05) increased in the rush immunotherapy group before the pollen season and did not vary significantly in the other groups.

Adolescent↗
PubMed1984

Time course of the changes in striatal acetylcholine levels induced by pergolide and haloperidol after lesion of the nigrostriatal dopaminergic pathways in the rat.

Lesion of the nigrostriatal dopaminergic pathway in the rat by 6-hydroxydopamine enhances the ability of pergolide to increase striatal acetylcholine levels and prevents the haloperidol-induced decrease in acetylcholine concentrations. This supersensitive response of striatal cholinergic cells is already maximal 6 days after lesion but tends to decrease thereafter. As the time course of the development of the supersensitivity of cholinergic cells differs from that of increased dopamine binding site density, the two are probably not causally related, the former reflecting rather a change occurring beyond the dopamine recognition site.

Acetylcholine↗
PubMed1984

Amino acid sequence of a new mitochondrially synthesized proteolipid of the ATP synthase of Saccharomyces cerevisiae.

The purification and the amino acid sequence of a proteolipid translated on ribosomes in yeast mitochondria is reported. This protein, which is a subunit of the ATP synthase, was purified by extraction with chloroform/methanol (2/1) and subsequent chromatography on phosphocellulose and reverse phase h.p.l.c. A mol. wt. of 5500 was estimated by chromatography on Bio-Gel P-30 in 80% formic acid. The complete amino acid sequence of this protein was determined by automated solid phase Edman degradation of the whole protein and of fragments obtained after cleavage with cyanogen bromide. The sequence analysis indicates a length of 48 amino acid residues. The calculated mol. wt. of 5870 corresponds to the value found by gel chromatography. This polypeptide contains three basic residues and no negatively charged side chain. The three basic residues are clustered at the C terminus. The primary structure of this protein is in full agreement with the predicted amino acid sequence of the putative polypeptide encoded by the mitochondrial aap1 gene recently discovered in Saccharomyces cerevisiae. Moreover, this protein shows 50% homology with the amino acid sequence of a putative polypeptide encoded by an unidentified reading frame also discovered near the mitochondrial ATPase subunit 6 gene in Aspergillus nidulans.

ATP Synthetase Complexes↗
PubMed1984

Evidence for Host Genome Involvement in Cytokinin Metabolism by Male and Female Cells of Mercurialis annua Transformed by Strain 15,955 of Agrobacterium tumefaciens.

When male and female individuals of a dioecious species Mercurialis annua L. were inoculated with the same strain of Agrobacterium tumefaciens (15,955), the corresponding tumor tissues of each sex clearly differed in their endogenous cytokinin content; only the male tumors had a morphogenetic feminizing effect on male flowers.In male tumor tissues, zeatin (Z) in higher quantity than ribosyl-zeatin (RZ) became the major metabolite in contrast with the general situation for crown-galls; the female tumor tissues were characterized by an increase of total endogenous cytokinins and by the appearance of some specific metabolites such as a methyl-thio-Z and several glycosylated Z derivatives that had not been detected in healthy apices.In both male and female tumor tissues, the cis form of RZ, present in healthy apices as 30% of trans-RZ form, was no longer detectable.Quantitative and qualitative differences characterize male and female tumor tissues (host genes expression) but since differences also appeared between healthy male and female apices and their corresponding tumor tissues (TDNA gene expression), it can be tentatively concluded that a complex interaction between host cytokinin genes and those of TDNA control the endogenous metabolism of tumor tissues.

Journal Article↗
PubMed1984

Allergy in the Mediterranean area. I. Pollen counts and pollinosis of Montpellier.

The climatic conditions of the Mediterranean area result in vegetation and pollen very different from that of the other parts of Europe. The pollen content of the atmosphere of Montpellier, southern France, was examined using a filter sampler which was shown to be more efficient than most of the current devices for air sampling. Pollen counts were subsequently compared with pollinosis of patients born and living in and around Montpellier. The mean annual pollen counts showed that grass pollens and Cupressaceae pollens (cypress and juniper) are the highest. Some Mediterranean pollens (Oleaceae, London plane, Parietaria) are also important. Plantain and oak pollens are also present in relatively large amounts. Grass pollen allergy was found to be present in 86.5% of pollen-allergic patients. It was followed by plantain, Parietaria, Oleaceae, London plane and Cupressaceae pollens which were allergenic in 13-36% of pollen-allergic patients. Oak and pine pollens were present in large quantities in the counts but few persons were sensitive to oak and none to pine. By contrast, some patients had positive skin tests to alfalfa, red clover, acacia and lime tree pollens though these pollens were almost absent from the counts. In a few cases local sources of these pollens could account for the positive skin tests but cross-sensitivities could also occur. In summary, pollinosis of the Northern Mediterranean area is intermediate between the southern part of the area and the other parts of Europe.

France↗
PubMed1984

Tests for allergy to housedust.

In an attempt to find a satisfactory combination of method and antigen extract for tests of hypersensitivity to housedust, variations of skin test, RAST, histamine release and basophil degranulation tests have been used to test efficacy of five commonly used extracts of housedust or its components. The Lincoln Multitest for skin prick tests in its present form induced too much trauma for type-I hypersensitivity tests, though it has advantages for comparison of several extracts. Histamine release and two versions of basophil degranulation tests all gave good results but not consistently. RAST gave the best correlation between all extracts, but neither the in vivo nor in vitro tests gave perfect concordance with sensitivity in all patients and all extracts.

Adult↗
PubMed1983

Effect of tribenzylphosphate on the active phosphate transport and ATP synthesis in yeast mitochondria.

Tribenzylphosphate (TBP), a specific inhibitor of the high affinity system for Pi transport in yeast mitochondria, inhibits the active Pi transport measured by the energy-linked swelling. The dependence of the rate of oligomycin sensitive ATP synthesis as a function of the external Pi concentration shows two kinetic systems. The high affinity system, corresponds to the range of the external Pi concentration which stimulates the respiratory rate. TBP inhibits both this system and the state 4 leads to state 3 transition.

Adenosine Triphosphate↗
PubMed1982

Dissociate destruction of noradrenaline and dopamine descending projections in the thoracic spinal cord of the rat.

Intracisternal administration of 6-hydroxydopamine to male Wistar rats produced a near complete depletion of noradrenaline levels, as measured by a radioenzymatic assay in micropunches sampled from the dorsal, lateral and ventral horns of the thoracic spinal cord. This drastic effect was reversed by pretreatment with desipramine, a pharmacological inhibitor of noradrenergic neuron uptake. Surprisingly, dopamine content was not significantly reduced. The question as to whether such a lack of concomitant dopamine decrease might be inherent to the dopamine assay itself could be answered by the results obtained with both pharmacological (reserpine) treatments and interference determinations in the dopamine assay. The relative potency of 6-hydroxydopamine to destroy noradrenergic and dopaminergic neurons might account for their differential behavior. Conversely, a large midbrain section performed by knife cut could decrease both dopamine and DOPAC (one of its major acid metabolites) in the thoracic lateral horn and partly in the ventral one. The noradrenaline content was not reduced. Results are discussed in light of recently reported data on dopaminergic descending projections to the spinal cord. The lesion procedures presented here seem to provide valuable tools to dissociate noradrenergic from dopaminergic spinal projections, which is necessary for further anatomical and functional studies on these systems.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Staphylococcal and human dander IgE antibodies in superinfected atopic dermatitis.

Ten patients (Group 1) with Staphylococcus aureus superinfected atopic dermatitis (SAD) were compared with three control groups without SAD. One control group (Group 2) was comprised of ten atopic patients with total IgE levels of greater than 1000 u/ml, another control group, of six atopic patients (Group 3) with total IgE levels of less than 1000 u/ml and a third group, of ten non-atopics (Group 4), five of whom were infected with Staphylococcus aureus. Total and specific anti-staphylococcal IgE levels and anti-human dander IgE were high in Group 1. Specific IgE levels to S. aureus were slightly increased in some Group 2 patients but were normal (less than 7%) for Group 3. No specific IgE to human dander antigen was detected in either Group 2 or Group 3. In the non-atopic control group (Group 4), six out of ten patients had both low total, and specific IgE antibodies to both staphylococcal, and human dander antigens. Two had increased total IgE and specific anti-staphylococcal IgE antibodies, and two more with a severe, chronic infection, also had anti-staphylococcal IgE antibodies. In SAD patients, a good correlation was seen between cutaneous basophil hypersensitivity and high specific IgE antibodies against staphylococcal and human dander allergens. Delayed type hypersensitivity reactions to staphylococcal antigen were negative or poorly positive in the SAD group by comparison to controls. A paradoxical anaphylactic type of response to the offending bacterial agent in SAD patients, associated with 'auto-atopy' to human dander, is discussed.

Antibodies, Bacterial↗
PubMed1982

New mutants resistant to glucose repression affected in the regulation of the NADH reoxidation.

Spontaneous mutants resistant to vanadate, arsenate or thiophosphate were isolated from a haploid strain of Saccharomyces cerevisiae. These three anions have an inhibitory effect on some mitochondrial functions and at the level of glyceraldehyde 3-phosphate dehydrogenase, a glycolysis enzyme. All the selected mutants had the same phenotype: they were deficient in alcohol dehydrogenase I, the terminal enzyme of the glycolysis, and possessed a high content of cytochrome c oxidase, the terminal enzyme of the respiratory chain. Moreover, cytochrome c oxidase biosynthesis had become insensitive to the catabolite repression, while the biosynthesis of the other enzymes sensitive to this phenomenon were always inhibited by glucose. Metabolic effects of this pleiotropic mutation manifested themselves in the following ways. 1. Growth rate and final cell mass were enhanced, compared to the wild type, when cells were grown on glucose or on glycerol, but not on lactate or ethanol. 2. Growth under anaerobiosis was nil and mutants did not ferment. 3. Mitochondrial respiration of the mutant strains was identical to the wild type with succinate or 2-oxo-glutarate as substrate, and weak with ethanol. But with added NADH, respiration rate of the mutants was higher than that of the wild type and partially insensitive to antimycin, even when cells were grown in repression conditions. It is postulated that in mutants strains, NADH produced at the level of glyceraldehyde 3-phosphate dehydrogenase, failing to be reoxidized via alcohol dehydrogenase, could be reoxidized with a high turnover owing to the enhancement of the amount of cytochrome c oxidase. Since NADH reoxidation is partially insensitive to antimycin, a secondary pathway going from external NADH dehydrogenase to cytochrome c oxidase is suggested.

Alcohol Oxidoreductases↗
PubMed1981

Supersensitivity time course of dopamine antagonist binding after nigrostriatal denervation: evidence for early and drastic changes in the rat corpus striatum.

The sensitivity of the [3H]haloperidol binding technique can be greatly increased by focusing tissue sampling on striatal regions where dopaminergic innervation is the richest. Such sampling is provided from pooled microdiscs punched out of 8 serial 500 micrometer thick sections of the rat brain. With these conditions, the density of receptor sites (Bmax) was found to be twice that of the whole striatum, without modification of the apparent dissociation constant (Kd) and of the Hill's slope. Such a procedure applied to rats with complete 6-hydroxydopamine-induced unilateral nigrostriatal lesions showed a moderate decrease in Bmax in the lesioned side up to 6 days after surgery, whereafter the value of Bmax increased progressively up to the thirtieth day, being then 160% over the control value. Conversely, the apparent Kd decreased significantly from the second to the sixth day postsurgery in the lesioned side, and then increased moderately up to the tenth day and drastically from the twenty-first to the thirtieth day. No change was observed in the corresponding intact side. The modifications appeared chronologically compatible with those corresponding to the behavioral denervation supersensitivity, evidencing drastic binding changes as compared with the whole striatum. The unexpected variations in Kd observed were well correlated with those in Bmax, suggesting that the new available binding sites might be of lower affinity. In the light of all these results, a hypothetical model is proposed.

Animals↗