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Biomedical subjects

P Lorimier

Publications and source records attributed to P Lorimier.

13 recordsLinked to original sources
PubMed1994

F(ab) secondary antibodies: a general method for double immunolabeling with primary antisera from the same species. Efficiency control by chemiluminescence.

We propose a general solution to the problem of using antibodies originating in the same species for double immunohistochemical labeling. It relies on the use of a two-step protocol in which a secondary polyclonal monovalent F(ab) antibody present in the first step blocks access in the second of the secondary antibody to the primary antibody, which is continuously present from the first step. The monovalence of the F(ab) fragment eliminates the possibility of its linking the primary antibody from the second step. We designed two efficiency tests to explore the limits of the method by the very sensitive chemiluminescent system applied to sections of human pituitary tissue. They confirmed both the validity of the method and the necessity of adapting working conditions to obtain a complete lack of interference.

Animals↗
PubMed1993

Enhanced chemiluminescence: a high-sensitivity detection system for in situ hybridization and immunohistochemistry.

The breakthrough of chemiluminescence in the field of solution immunoassays and transfer membranes prompted us to explore whether a light-based detection system could provide a gain in sensitivity over chromogenic and FITC markers for nucleic acid and protein detection on histological preparations. A Hamamatsu device and an enhanced chemiluminescence (ECL) luminol substrate of the peroxidase were used to detect epithelial and endothelial components by immunohistochemistry (IHC) and for in situ hybridization (ISH) of papilloma virus DNA. The accuracy of the signal was compared to that obtained with DAB-peroxidase, silver-enhanced DAB-peroxidase, NBT-BCIP-alkaline phosphatase, and FITC. Our results demonstrated the feasibility and high sensitivity of luminescence detection for histological preparations. In part due to the ultrasensitive videocamera and photon-counting imaging, interpretable and reproducible results were obtained within counting times shorter than 5 min, and with dilutions of the primary antibodies 100- to 10,000-fold greater than those used for chromogenic and FITC reactions. As for ISH, with identical concentrations of the HPV 18 DNA probe on HeLa cells, labeling was apparent by luminescence but undetectable with the chromogen. The morphological resolution allowed a discriminatory analysis of the signal. Therefore, at the light microscopic level, enhanced chemiluminescence offers an appealing alternative to FITC and chromogenic markers for detection and quantification of low-concentration molecules.

Antibodies, Monoclonal↗
PubMed1992

Ultrastructural localization of the major components of the extracellular matrix in normal rat nerve.

In this study we determined the ultrastructural distribution of the various components of the extracellular matrix (laminin, fibronectin, Type I, III, and IV collagens) of the normal peripheral nerve in adult rat. The localization of these macromolecules was investigated in basement membranes as well as in different areas of epi-, peri-, and endoneurium, by use of a pre-embedding immunoperoxidase method.

Animals↗
PubMed1992

[Hyperventilation syndrome: current advances].

The hyperventilation syndrome has been described for half a century but clearly remains underdiagnosed. Its acute manifestation is easily diagnosed ("the tip of the iceberg") but its recognition in numerous subtle forms requires a particular degree of alertness on the part of the clinician ("the hidden part of the iceberg"). The incidence of this syndrome in the general population varies according to different authors as between 6-11% and may mimic diverse organic disorders. The physiological consequences of hyperventilation are reviewed as well as their contribution in the clinical picture. The aetiology of the syndrome and its links with organic pathology or psychiatric disturbances continues to be debated. Is hyperventilation the expression of abnormal respiratory function or a preferred manifestation of anxiety? This article discusses and reviews the variety of tests which enable the presumptive diagnosis to be confirmed. The response to the proposed treatments is generally excellent when one takes account of the numerous possible options. These include comportmental therapies such as respiratory re-education, the utilisation of betablockers and psychotrophic drugs or psychotherapy.

Bronchial Provocation Tests↗
PubMed1991

Quantitative image analysis with densitometry for immunohistochemistry and autoradiography of receptor binding sites--methodological considerations.

Major technical progress in the development of computer-based image analysis has made possible the entry of autoradiography and immunohistochemistry into a new era where quantification by densitometry has become easily accessible. Autoradiography could become quantitative and displayed adequate reproducibility with the help of emulsion-coated films and the use of scales of standards of known radioactivity exposed and analyzed in parallel to the tissue sections. Immunohistochemistry after revelation by a color-based enzymatic technique can also become quantitative, providing that standardization of the crucial steps of the procedure and calibration through a parallel treatment of a scale of antigen standards can be ensured. Such an approach is described here in the rat with reference to tyrosine hydroxylase (TH), the main synthesizing enzyme for catecholamines, and with dopamine (DA) itself, a catecholaminergic neurotransmitter. The different parts of the procedure, which can influence the results, such as the fixation of the animals by perfusion and the evaluation of the fluctuations via the calibration curve, are discussed in detail. Biological validation of the proposed procedure is described by reference to experiments already well documented biochemically, such as the induction effect of reserpine on TH in the rat locus coeruleus and the depleting effect of alpha-methyltyrosine (AMPT), a well-known blocker of TH activity, on rat striatal DA content. Finally the importance of restricting the measurements to the (pseudo)linear portion of the calibration curve is illustrated by the autoradiographic identification of the differential intrastriatal repartition of the dopaminergic D1 and D2 receptor sites, particularly the dual patch-matrix compartments.

Animals↗
PubMed1991

[Value of monitoring of tracheal respiratory sounds in the diagnosis of nocturnal respiratory dysrhythmias].

Twenty-six patients underwent a polysomnigraphic study allowing sleep staging and respiratory events scoring with the use of the oronasal flow, abdominal, thoracic and total displacement (Respitracet), and ear oximetry. Moreover the patients were also equipped with a tracheal microphone giving a power rectified envelope (sonospirogram). Eleven patients showed abnormal respiratory events that were scored by visual lecture using all respiratory parameters (excluding the sonospirogram) and were classified as obstructive central and mixed apneas-hypopneas. Periodic breathing was also appreciated. Detection of the same events was tried with the sonospirogram alone. The sonospirogram could accurately detect snoring and periodic breathing and finally central obstructive mixed apnea (the apneic index being well correlated: p less than 0.001 as well as the mean apnea duration: p less than 0.005). In contrast hypopneic events related to snoring could not be accurately appreciated. We conclude that a sonospirogram may be useful for the detection of abnormal respiratory events when used alone (screening) as when added to other respiratory signals.

Adult↗
PubMed1991

[Contribution of polysomnography in the assessment of patients with chronic obstructive bronchopneumopathy].

15 COPD patients underwent a polysomnographic study demonstrating poor quality of sleep, a mean of SAO2 of 88.8 +/- 3.9% and a apneic-hypopnea index (AHI) of 5.7 +/- 11.8. AHI was higher in sleep stages I and II than in REM sleep. SAO2 showed a progressive drop when going from an awake stage to REM sleep. Respiratory events responsible for the most important desaturation where mostly observed in REM sleep and corresponded in 8 patients to obstructive events (overlap syndrome). The lower mean SAO2 in REM probably explains the best the importance in desaturation related to the respiratory events (Hb dissociation curve). Ear oximetry recordings however interesting are not able to quantify and recognise correctly the respiratory events. Therefore a polysomnographic study remains necessary in order to diagnose adequately the overlap syndrome.

Electrophysiology↗
PubMed1990

Cyclic haemodynamic and arterial blood gas changes during Cheyne-Stokes breathing.

A 74-year-old patient presented with congestive heart failure and continuous periodic breathing. Left ventricular ejection fraction was 20% and the lung-to-brain circulation time was prolonged to 35 s. We report on the phasic changes of the patient's arterial blood gas tensions and on the periodic fluctuations of pulmonary artery pressures and cardiac output that we observed during Swan-Ganz catheterisation.

Aged↗
PubMed1990

A human monoclonal IgM with autoantibody activities against heparan sulphate and the mitotic spindle.

A monoclonal IgM kappa from a patient with Waldenström's macroglobulinaemia (IgM-Rod) was found to react at temperatures below 28 degrees C with all tissue basement membranes and the cell coat of non-haematopoietic cells. IgM-Rod antibody was directed against heparan sulphate side chains of heparan sulphate proteoglycans as shown by binding in a solid-phase ELISA to heparan sulphate glycosaminoglycans but not to other purified subcomponents of the extracellular matrix; and by specific inhibition of the observed reactivity by heparitinase treatment. IgM-Rod showed cross-reactivity by indirect immunofluorescence with an as yet unidentified structure expressed in the nucleus during cell division and becoming associated with the mitotic spindle apparatus. The co-existence of both binding activities for heparan sulphate and nuclei determinants in the same IgM molecule was deduced from adsorption-elution experiments and from the inhibitory effect of a mouse monoclonal anti-idiotypic antibody directed against the paratope of IgM-Rod.

Antibodies, Anti-Idiotypic↗
PubMed1990

[The value of a visual score of dyspnea in the functional follow-up of asthma patients].

6 severe asthmatic patients were followed for 24 hours using a visual analogue score of dyspnoea and by studying the airway resistance. Their treatment consisted either of two inhalations of placebo or of two inhalations of fenoterol every 5 hours. It appeared that there was only a correlation between the dyspnoea score and respiratory function score for the largest variations of resistance induced by inhalation of sympathicomimetics. The inverse was that altered function offering only small fluctuations was not correlated with a sensation of dyspnoea.

Adult↗
PubMed1989

[Medical treatment of sleep apneas].

The authors review the medical treatment of the sleep apnea syndrome. They also discuss the mechanical possibilities such as continuous positive airway pressure ventilation. The limits of these various treatments are presented in order to better define the indications for upper airway surgery.

Humans↗