Imprégnations rapides à la Nigrosine applicables à la micro-ecologie des surfaces

Summary The ecology of primary biological coatings (fouling films) is an important aspect of benthic ecology in general. Life in a fouling film is, to a large extent, governed by physico-chemical laws of contact surfaces and surface tension. These laws apply also to the microecology of the mesopsammon and surface microplankton. The conditions common to these ecological situations enforce common characteristics, both morphological and physiological, upon the organisms which inhabit them. Many of these organisms are therefore subject to certain general techniques.Nigrosin is employed as an impregnating agent, and the speed of activity of the micelles of nigrosin is under the control of 1) the colloidal nature of the medium, and 2) alteration of cytoplasmic structures by the action of formalin added to the solution as a fixative.The stain blackens a variety of organites having a filamentous ultrastructure: cilia, flagella, trichocysts, rhabdites, cnidocysts, spiny processes of thecae and shells, capsules, cuticles and cuticular setae. The excess nigrosin surrounding the specimen may be removed completely by simple washing.Two particular situations are discussed: that of microbiocoenoses which develop at the point of contact of water and air (for example, bacterial films) and that of glass slides immersed in water with a view to studying the organisms which colonize surfaces in a particular habitat.The method has been applied also for studies of plankton in general, to demonstrate the liberation of flagellate bodies by certain algae, and for preparation of mounts of various organisms such as rotifers, gastrotrichs and nematodes. The method is very useful for quickly obtaining a comprehensive picture of the protozoan fauna in ecological studies.     

Hommage à rené delépine à l'occasion de son départ à la retraite

A tribute to René Delépine on the occasion of his retirement. The career of René Delépine is reviewed on the occasion of his retirement. When he was a student, a meeting with Jean Feldmann led to a lifelong inclination towards phycology. Eventually appointed to the position of assistant professor at the University of Paris-VI (University Pierre-et-Marie-Curie), René Delépine worked and published primarily on the taxonomy of antarctic and subantarctic marine algae but he was also interested in seaweed aquaculture and utilizations. After organizing the national colloque ValVA (Valorisation des végétaux aquatiques), he became increasingly involved in the commercial application of seaweeds. His main activity, however, remained university teaching for which he was always enthusiastic, especially for teaching in the field and on the subject of the utilizations of algae. A list of his publications is given at the end of this article.     

Efficacité de la mémoire associative inhérente à la potentiation post-tétanique

An associative memory is modeled in networks of cells that are assumed to have the short-term plasticity of the neuromuscular junction of the frog. The data relating synaptic transmission efficiency and stimulation frequency for post-tetanic potentiation of the neuromuscular junction are represented by polynomial expansions. Simulation of storage and retrieval demonstrates that functional associative memory is feasible based on this particular synaptic plasticity. Retrieval reaches a maximum efficiency at a delay of three minutes after storage and is lost after about 9 min. The signal to noise ratio of the retrieved pattern drops steadily as additional associations are stored in memory but retrieval appears to be possible with up to four stored associations. Although the data are derived from synapses not normally proposed as a basis for memory functions, the results here will generalize to other synaptic junctions located more centrally that have similar characteristics. This simulation technique allows the efficiency of associative memory based on various types of synaptic plasticity to be evaluated.     

Contribution à la systématique du genre Pichia

The presence of intracellular osidases, nitrite and nitrate reductases, vitamin requirements and GC content in the DNA, have been investigated for in 18 species of Pichia.According to their typical characters and their biocaracters, a pattern is suggested for the integration of these new species into the formerly existing groups of the genus Pichia. A new way of classifying the species of the genus Pichia is proposed.     

Contribution à l'étude de la bryoflore Lorraine

Contribution to the knowledge of the bryophyte flora of Lorraine (France). The bryophyte flora of Lorraine (France), which was not extensively studied during the second half of this century, has been visited again over the last four years. Seligeria acutifolia Lindb. has been collected for the first time in that region. New localities of several rare or poorly known bryophytes are given. A perspective view is proposed as to the future of bryological research in Lorraine.     

Intérêt de la tomoscintigraphie cardiaque à la 123I-mIBG couplée à la perfusion myocardique dans le diagnostic de l’atrophie multisystématisée

ObjectiveThe aim of this prospective study is to assess the pertinence of using ¹²³I-mIBG myocardial tomoscintigraphy coupled with perfusion scintigraphy as a diagnostic tool, to discriminate between multiple system atrophy (MSA) and idiopathic Parkinson's disease (PD) at first guided by clinical data and L-DOPA tests.Material and methodsForty patients, aged from 43 to 78 years (median 62 years) with Parkinson's syndrome were studied. Nineteen had a diagnosis of PD (criteria of brain bank) and 21 AMS (Gibbs criteria). All were given test to acute L-DOPA. Chest-centered planar imaging (128 × 128 matrix, 5 minutes of duration) is performed at 1 hour and 4 hours after injection of 220 MBq of ¹²³I-mIBG, in addition a non-synchronised tomoscintigraphy (64 × 64 matrix, 32 images of 50 seconds , zoom 1.45) was performed after the 4th hour and 15 minutes after injection of 200 to 400 MBq of ^99mTc-tetrofosmin. Besides neurological data, the parameters retained for comparison purposes with ¹²³I-mIBG cardiac tomoscintigraphy were patients’ age, duration of disease and L-DOPA test results. Two regions of interest (ROI) identical in size and in shape are used for ¹²³I-mIBG uptake quantifications (H/M and washout [Wo]). The first one was placed in projection of mediastinum (M) and the other one in projection of heart (H).ResultsWe found an overall decreased uptake of the myocardial ¹²³I-mIBG without perfusion abnormality in 15 of 19 patients with PD and 11 among them were L-DOPA sensitive (L-DOPA test greater than 30%). Normal tracer uptake with ¹²³I-mIBG associated with an almost quite normal perfusion was seen in 15 of 21 patients with MSA and they were little or not L-DOPA sensitive (L-DOPA test less than 30%). Therefore, 10 discordant cases (25%) between cardiac scintigraphy and clinical evolution of disease with also discordant L-DOPA tests were observed. In the PD group, quantification of data enhanced the diagnostic decision with low heart to mediastinum ratio (H/M) (1.32 ± 0.15 at the early stage and 1.25 ± 0.13 at the later stage). In the MSA group, the uptake of ¹²³I-mIBG (1.66 ± 0.43 at the early stage and 1.72 ± 0.42 at the later stage) was comparable to literature data, however, with significant inter-individual variations. The association of data of scintigraphy with L-DOPA test allows to improve sensitivity in 84% and specificity in 90.5%.ConclusionOur prospective study of 40 cases shows the relevance of cardiac sympathetic postganglionic imaging with ¹²³I-mIBG coupled with myocardial perfusion scintigraphy to discriminate between MSA and PD with a higher sensitivity (71.4%) compared to the test with L-DOPA but a lower specificity (78.9%) than the L-DOPA. The difficulty of diagnosis is firstly linked to damage occurring to both the pre- and postganglionic sympathetic systems in patients with MSA and secondly to the integrity of the sympathetic nerve endings in patients with PD. However, the association of data of scintigraphy with L-DOPA test show a significant improvement of sensibility (84%).     

La filiation et l'aide médicale à la procréation

Kinship following artificial insemination by unknown donor defines the child's mother and father as unknown. Although it could have been possible to construct this kinship on the model of adoption, the model adopted was that of blood and organ donation, which completely erases the donor's identity so that the recipient can take complete possession of the donated substance. But is gamete donation the same thing? Gamete donation concerns procreation and the parents' sexuality. Would it be possible to no longer consider the parents' sexuality to be exclusively reproductive sexuality allowing recognition of the progenitors alongside the mother and father?     

Évolution de la cellule normale à la cellule cancéreuse prostatique hormonodépendante–hormono-indépendante

The prostatic gland is androgen-dependent. The role of androgens in the development, function and pathology of the prostatic gland (benign hypertrophy or cancer) derives from: direct evidence, resulting from experimental models (in vitro–in vivo) or from the biological analysis of normal and pathological human prostatic tissues. These data make it possible to describe the current point of our knowledge concerning the molecular, cellular, and tissular mechanisms involved; indirect data resulting from epidemiologic and clinical studies describing the impact of androgen suppression or supplementation on the prostatic gland. At the experimental level, it is generally allowed that the growth of prostate is controlled by androgens (testosterone and its metabolites). A suitable circulating testosterone level is necessary to maintain the growth, development, differentiation and function of the prostatic gland. Bilateral orchidectomy induces programmed cellular death (apoptosis) and the gland involution; exogenic testosterone administration is then able to induce the prostatic growth up to the normal level. The same applies when an impubescent animal is treated. The response of prostate to exogenic testosterone thus does not produce a growth beyond the normal volume, which is maintained by balance between proliferation and cellular death in the presence of physiological levels of androgens. The study of the mechanisms of regulation of the prostatic growth provides a fundamental justification to the chemical and hormonal treatments used by the urologists in the treatment of prostate benign hypertophy and cancer. Within the framework of the androgenic deficit related to age, a doubt persists about a potentially harmful action of the substitute androgenic treatment on prostate.     

Quand l’évolution parle à la biologie fondamentale

Like many results in comparative anatomy, the works on bone histology led by Armand de Ricqlès have found their whole sense within the framework of the theory of evolution. It seems to be the same thing in genomics and molecular biology. However, some examples show that the fluidity of genomes is not realized by the same processes in eukaryotes and in prokaryotes. In the first taxon, transposons play a fundamental role, since in the other case horizontal gene transfers are essential. These dynamics seem to be necessary for understanding the bases of genomic evolution both from fundamental and applied points of view.     

Effets d’une exposition à la Vinclozoline et à la Génistéine de la gestation à l’âge adulte sur la fonction de reproduction du ratWistar mâle: protocole et résultats préliminaires

Current evidence indicates that endocrine disrupters (EDs) can induce adverse effects on the male reproductive tract in various mammalian species. Recent reports indicate deterioration in male reproductive health in several human populations, but the evidence for a causal link with endocrine disruption is still weak. In addition, the experimental conditions of most of the reportedin vivo studies are not representative of environmental exposures (for example, high doses, short-term exposure, a single ED) and the mechanisms by which EDs disrupt the reproductive system are poorly understood. The objective of the present study is to develop an animal model to assess the reproductive effects and study the putative cellular and molecular mechanisms involved after exposure to genistein (phytoestrogen) and vinclozolin (fungicide with a known antiandrogenic potential) alone or in combination. The study will be performed in male Wistar rats, with administration of low and high doses of the compounds from conception to adulthood and a subset of the males in each treatment group will be mated with unexposed females. We plan to assess the level of sperm production, histology of the reproductive organs, motility and morphometry of spermatozoa and hormone levels, as well as DNA fragmentation of spermatozoa and determination of the number of germ cells, Sertoli cells and the diameters of seminiferous tubules. Estrogen, androgen, progesterone and FSH receptors will be detected and quantified and the level of testicular apoptosis and several apoptosis pathways will be studied to determine the putative cellular and molecular mechanisms involved. The preliminary results confirmed the developmental effects previously reported for high doses of vinclozolin. More interestingly, they indicated a number of deleterious effects for male rats exposed to low dosages alone or mixtures of low and high dosages compared to controls and rats exposed to high dosages alone. For example, a number of developmental anomalies of the genitalia were observed and a significant decrease of sperm motility and motion and fertilizing ability were observed. These preliminary results provide evidence that chronic exposure to environmental levels of EDs or mixtures of EDs have a detrimental impact on the male reproductive tract. The next step involves assessment of the anatomical disorders and the study of some of the cellular and molecular mechanisms possibly involved.     

Aspects originaux de la trichinose domestique à partir d'une infestation familiale découverte à Montréal

An outbreak of domestic trichinosis occurred in an Italian family living in Montreal. All patients had a fever, facial edema and extreme eosinophilia, and results of serologic tests were positive. Larvae of Trichinella spiralis were seen in a muscle biopsy from one of the patients. The discussion emphasizes some characteristic clinical, serologic and histopathological aspects.     

Composition lipidique membranaire durant la préparation de spermatozoïdes à la fécondation

The final modifications that the spermatozoa undergo correspond with the destabilization of their plasma membrane. This indispensable step facilitates the fusion of membranes and primes the signal transduction during fertilization. This destabilization is composed of a series of changes and modulation of the lipids in membranes such as cholestérol, phospholipids and glycolipids. Several differences exist in the lipid composition of the plasma, acrosome, nuclear and mitochondrial membranes of spermatozoa. The principal membrane phospholipids are phosphatidyl choline, phosphatidyl ethanolamine and sphingomyelin. Plasma membrane of sperm is also rich in polyunsaturated fatty acids (PUFA) linked to phospholipids. Such as C₁₈∶2n?6, C₂₀∶4n?6 and large amounts of docosahexaenoic acid (C₂₂∶6n?6). The amount of membrane lipids in human sperm varies considerably between patients. This variation, could influence certain functional properties of the sperm cells such as their ability to undergo capacitation, the acrosome reaction and the fusion between sperm and oocyte membranes. The lipid composition of the human sperm cell can be altered during the process of freezing-thawing. A significant decrease in phospholipids (phosphatidyl choline, phosphatidyl ethanolamine), and PUFA in particular docosahexaenoic acid and arachidonic acid was observed. Human spermatozoa have a molar cholestérol/phopholipid ratio ≤1.0, and reduces during capacitation due to loss of cholestérol. In addition, the decrease in the levels of cholestérol and the methylation of phospholipids is involved in the modification of membrane fluidity and in the maturation of the sperm plasma membrane receptors. Therefore it seems that the methylation is important for the fusion between sperm and oocyte membranes. Intrinsic sperm phospholipase A2 also plays a role in the destabilization of the plasma membrane by producing of lysophospholipid. Therefore this enzyme and free fatty acids are believed to play a role in the acrosome reaction, an indispensable event facilitating the fusion between sperm and oocyte membranes.     

De la gonorrhée à la blennorragie: Les grandes étapes historiques

This paper examines the history of gonorrhoea and its treatment. It is very probably a very ancient disease that was confused with syphilis for centuries.     

Cytochrome P450 et activation génétique — de la pharmacologie à l’élimination du cholestérol et à la régression de l’athérosclérose

Background

Lipoproteins are closely associated with the atherosclerotic vascular process. Elevated levels of highdensity lipoprotein cholesterol (HDL-C) and apolipoprotein AI (apo AI) in plasma indicate a low probability of coronary heart disease (CHD) together with enhanced longevity, and elevated levels of low-density lipoproteincholesterol (LDL-C) and apo B indicate an increased risk of CHD and death. Studies linking gene activation and the induction of cytochrome P450 with elevated plasma levels of apo AI and HDL-C and lowered plasma levels of LDL-C presented a new potential approach to prevent and treat atherosclerotic disease.

Objective and methods

This is a review aimed at clarifying the effects of P450-enzymes and gene activation on cholesterol homeostasis, the atherosclerotic vascular process, prevention and regression of atherosclerosis and the manifestation of atherosclerotic disease, particularly CHD, the leading cause of death in the world.

Results

P450-enzymes maintain cellular cholesterol homeostasis. They respond to cholesterol accumulation by enhancing the generation of hydroxycholesterols (oxysterols) and activating cholesterol-eliminating mechanisms. The CYP7A1, CYP27A1, CYP46A1 and CYP3A4 enzymes generate major oxysterols that enter the circulation. The oxysterols activate — via nuclear receptors — ATP-binding cassette (ABC) A1 and other genes, leading to the elimination of excess cholesterol and protecting arteries from atherosclerosis. Several drugs and nonpharmacologic compounds are ligands for the liver X receptor, pregnane X receptor and other receptors, activate P450 and other genes involved in cholesterol elimination, prevent or regress atherosclerosis and reduce cardiovascular events.

Conclusions

P450-enzymes are essential in the physiological maintenance of cholesterol balance. They activate mechanisms which eliminate excess cholesterol and counteract the atherosclerotic process. Several drugs and nonpharmacologic compounds induce P450 and other genes, prevent or regress atherosclerosis and reduce the occurrence of non-fatal and fatal CHD and other atherosclerotic diseases.     

Réduction des effets de la respiration en imagerie TEP pulmonaire par une acquisition synchronisée à la respiration associée à une TDM en apnée

Respiratory motion causes a spread of lesion uptake over a larger area in Positron Emission Tomography (PET) images for moving structures. When CT images are used for attenuation correction of emission data, this motion may alter the quantization of PET images. We present the clinical results of a respiratory-gated PET processing “CT-based” method, which aims to improve PET-CT coregistration by using an additional breath-hold CT (BH-CT). The CT-based protocol consisted in a 10-min List Mode respiratory-gated PET acquisition, followed by an end-expiration BH-CT acquisition. During these two examinations, the respiratory signal was recorded continuously. Eleven pulmonary lesions were studied. Patients underwent both a standard clinical PET protocol (free breathing) and the CT-based protocol. The respective performances of the CT-based and clinical PET methods were evaluated by comparing the distances between the lesions’ centroids on PET and CT images. SUV_MAX (Standardized Uptake Value) and volume variations were also investigated. The CT-based method showed a significant reduction (p = 0.049) of centroid distances (mean relative change versus standard method: 49%). We also noted a higher SUV_MAX (mean change: 39%). Lesion volumes were significantly lower (p = 0.026) in CT-based PET volumes (mean change: 43%) compared with standard ones. The CT-based method improves PET-CT coregistration of pulmonary lesions. This protocol should lead to more accurate attenuation correction and thus improve SUV measurement.     

Aérosolthérapie à la kanamycine dans 200 cas de suppurations bronchopulmonaires

This paper describes the results obtained in 200 patients with bronchopulmonary suppurative diseases who received kanamycin aerosol therapy under intermittent positive pressure and in whom bacterial sensitivity study (antibiogram) was favourable.This method of treatment was well tolerated and was practically free of side effects. In most cases the improvement was rapid, was maintained and was often life-saving.The first series contained nine patients with pulmonary tuberculosis and a constant finding of sputum positive for Koch bacillus; four of these became negative after eight weeks of treatment. This suggested that kanamycin aerosol therapy had some effect on the Koch bacillus and that the study should be continued with a much larger group of patients with tuberculous suppurative pulmonary diseases to determine the efficacy of this antibiotic.     

Contribution à la connaissance des Desmidiées du Congo belge

Résumé Le présent travail s'occupe de 85 Desmidiées, dont la plupart ont été trouvées dans le matériel que j'ai recueilli au Congo, à Stanley-Ville.Quant aux Micrasterias, ce genre a été étudié avant tout sur du matériel provenant des environs de Léopoldville et recueilli par les Docteurs W. Bervoets et Fr. Evens. Une partie des déterminations et des figures ont été faites par le Dr. Evens. Je l'en remercie ici tout spécialement.Les espèces et variétés traitées se répartissent comme suit:Des 85 espèces trouvées dans le matériel examiné, 76 sont nouvelles pour le Congo et 5 variétés sont décrites comme nouvelles pour la science. Ce sont: Pleurotaenium subcoronulatum (Turner) W. & G. S. West, var. maximum Euastrum malmei Borge, var. congolense Micrasterias tropica Nordstedt, var. ndjiliensis van Oye & Evens Cosmarium obsoletum Reinsch, var. glabra Staurastrum orbiculare Ralfs, var. maxima De beaucoup d'espèces des données systématiques sont mentionées et discutées.La dispersion des différentes espèces est examinée là o\u on dispose d'assez de données.Enfin, des conclusions générales sont faites quand le matériel le permettait. En général, les données du travail permettent de confirmer les conclusions faites antérieurement.