Epidémie de dysentérie bacillaire.

An outbreak of bacillary dysentery in 1978 affecting 928 persons, most of whom were living in the village of St-Jacques, PQ, is described. An epidemiologic study suggested the water supply as the source of the infection, and it was established that the water carried by the municipal aqueduct was contaminated by feces containing the causal agent, Shigella sonnei. This epidemic, the largest mentioned in he Canadian medical literature, demonstrates how contagious this infection is.     

Prévalence d'Aeromonas spp. dans les gastro-entérites de l'enfant.

A selective medium and biochemical tests were used to search for Aeromonas spp. in the stools of 536 children, more than 90% of whom had "gastroenteritis", seen at Sainte-Justine Hospital, Montreal, in June or July 1986. The organism was found in seven children, six of whom had bloody diarrhea. One of the six, a 6 1/2-year-old boy, required intravenous alimentation and later manifested ulcerative colitis; the other five recovered. The remaining child, a 14-year-old boy, had synovitis of the knee and spondylarthritis. Two of the seven carried other enteric pathogens. The authors discuss the pathogenicity of Aeromonas spp., which is not very marked in temperate climates, in human summer diarrhea and its possible role in the development of ulcerative colitis.     

Testostérone circulante et cancer de la prostate. Revue de données récentes

In vitro andin vivo studies show that androgens stimulate prostate cancer. However, evidence from epidemiological studies of an association between circulating levels of androgens and prostate cancer risk has been inconsistent, but most studies have likely been undersized given that the association may be relatively weak. We review prospective studies on the association of serum levels of free and total testosterone, the principal androgen in circulation with risk of prostate cancer. No significant association between total or free testosterone and risk of prostate cancer was found in studies that together included 1,525 cases of prostate cancer and 4,349 controls. No support was found for the hypothesis that high levels of circulating testosterone within a physiological range stimulate development and growth of prostate cancer. Intraprostatic androgen metabolism may still be of importance for prostate cancer development.     

Variations de l'incidence des fractures de l'extrémité supérieure du fémur chez les personnes agées de la région de Québec.

To estimate the incidence of fracture of the proximal end of the femur in people aged 50 years or older living in the Quebec area in 1971, 1976 and 1981 we determined the number of admissions for such fractures to the 15 acute care hospitals in the region. From 1971 to 1981 the number of fractures increased by 71%; the increases for those aged 75 to 84 years and 85 years or over were 98% and 118% respectively. The variation is only partly explained by changes in sex and age distribution of the population; the incidence rates also increased. Among men aged 75 to 84 years the incidence rate per 1000 person-years rose from 2.63 in 1971 to 5.22 in 1981, an increase of 98%; the corresponding figures for men aged 85 years or more were 9.76 and 16.91, an increase of 73%. Among women aged 75 to 84 years the rate rose from 7.28 to 8.81, an increase of 21%; the corresponding figures for women aged 85 years or more were 20.40 and 24.27, an increase of 21% and 19% respectively.     

Comparaison de deux modes de prophylaxie de l'infection urinaire chez l'enfant avec le triméthoprime--sulfaméthoxazole.

Two types of prophylaxis of urinary tract infection with trimethoprim-sulfamethoxazole (TMP-SMZ) were studied in 72 children with recurrent urinary tract infections or vesicoureteral reflux or both. Daily prophylaxis only was used in 36 children and thrice-weekly prophylaxis only in 25 others, and 11 children received successively both types of prophylaxis. The same dosage was used in all cases: 2 mg/kg of TMP and 10 mg/kg of SMZ, given at bedtime. With daily prophylaxis the infection rate over 556 patient-months was 5.4 cases per 1000 patient-months, compared with 285.4 cases in the year before prophylaxis; side effects were noted in 11% of the patients during treatment. With thrice-weekly prophylaxis the infection rate over 381 patient-months was 15.7 cases per 1000 patient-months, compared with 313.6 cases in the year before prophylaxis; only 3% of the patients receiving this treatment had a side effect that was possibly drug-related. These results indicate that effective prophylaxis of urinary tract infection in children can be obtained with these two types of treatment.     

Étude de l'effet de la température sur la division des cellules séparées de feuilles deCalystegia sepium (L.) R.Br.

Cells mechanically isolated from homogenized leaves ofC. sepium dividein vitro. The rate of cell division is strongly influenced by temperature with the optimum between 31 and 34 °C. The rate of cell division increases proportionally with a rise in temperature up to 31 °C and is accompanied by a reduction in the length of the preparatory phase of the division. A supraoptimal temperature (40 °C) inhibits or stops the cell division which can be restored provided that the cells are transferred to 31 °C. If the preparatory phase to the commencement of cell division is accomplished at 17 °C the cells then exposed to 31 °C divide more rapidly than if they are exposed directly to 31 °C.     

Utilisation des céphalosporines comme antibioprophylaxie lors de césariennes.

Cefoxitin, a second-generation cephalosporin, was compared with cefazolin, a first-generation cephalosporin, and a placebo in a prospective, double-blind study of antibiotic prophylaxis in women undergoing nonelective cesarean section. In the groups that received cefazolin or the placebo there eas no statistically significant change in colonization of the cervix by aerobic bacteria by the fourth day after the operation, but there was a statistically significant increase in colonization by anaerobes. Cefoxitin had the opposite effect. Of the 14 postoperative infections in 11 patients, significantly more were in patients who had received the placebo; the numbers were too small to show a difference in effectiveness between the two antibiotics. Of the microorganisms implicated as the infectious agents, group B Streptococcus was the most frequent aerobe, and Peptostreptococcus and Bacteroides bivius were the most frequent anaerobes. Among the 15 patients for whom at least one perioperative specimen yielded positive culture results, a postoperative infection developed in 5 of the 6 who received the placebo, 2 of the 4 who received cefazolin and 1 of the 5 who received cefoxitin.     

Potentialités autotoxiques et allélopathiques de Cistus albidus L.

This study focuses on how allelopathic mechanisms may be involved in the floristic composition and dynamics of Cistus albidus shrubbery. Allelopathic potential of essential oils was measured for Lactuca sativa (toxicity for other species) and Cistus albidus (self-toxicity). These oils have little effect on germination but significantly increase, even in low quantities, the number of unviable seedlings and inhibit normal seedling growth. These results explain, at least partially, the existence of monospecific stands over several years and the lack of natural regeneration of the Cistus albidus populations. Bioassays performed using natural aerial leachates of Cistus albidus revealed no significant effects on the above-mentioned parameters. Leaching does not seem to be an important means of allelochemicals release. Nevertheless, essential oils have been quantified in litter and soil, indicating a possible occurrence of allelopathy in such ecosystems.     

La fondation de nouvelles sociétés parBellicositermes natalensis Hav.

Résumé D'après des élevages faits en Côte d'Ivoire, on décrit les premières étapes du développement pour les colonies deB. natalensis, en examinant particulièrement la construction du nid, la formation de la meule à champignon et des amas de sciure de bois.Le couple imaginal fondateur creuse une cavité souterraine (copularium) où il élève, sans prendre aucune nourriture, la première couvée. Les premiers petits ouvriers creusent alors des galeries ascendantes par où ils vont attaquer le bois à la surface du sol, à l'abri de galeries couvertes. Les premiers grands ouvriers apparaissent peu après.En une seule nuit, les ouvriers construisent, à l'intérieur du copularium, un habitacle régulier de forme ovoïde; la première meule à champignons, d'emblée fertile, est édifiée à l'intérieur de cet habitacle; la sciure de bois, réserve alimentaire, est amassée à l'extérieur.Les homologies sont établies entre les structures et cavités du jeune nid et celles de la termitière adulte.

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Summary Among the breedings carried out on the Ivory Coast, we could describe the first stages of development in colonies ofB. natalensis especially, by observing their nest-building, the growth of the fungus bed and of the heaps of saw-dust.The imaginal founder couple dig an underground cavity (copularium) in which they tend the first brood without taking any food themselves. Then, the first small workers dig ascending passage-ways through which they go in order to eat into the wood on the surface of the ground in the shelter of covered passage-ways. The first big workers come out soon after.In one night, inside the copularium the workers construct an even egg-shaped dwelling-place; the first fungus bed, at once fertile, is erected inside this dwelling-place; the heaps of saw-dust used as food-reserves are laid outside.Homologies are drawn between the structures and cavities of a young nest and those of an adult termitarium.

     

Bactéries hétérotrophes aerobies prélevées devant le delta du rhone. III. utilisation potentielle de differents substrats organiques comme source de carbone

Résumé Dans le cadre d'une étude portant sur un lot de 200 bactéries prélevées en surface dans des eaux eutrophes au débouché du Rhône en Méditerranée, les auteurs de carbone de 100 composés organiques appartenant à différentes classes chimiques.Dans l'ensemble, il est apparu que les familles de substances les mieux assimilées sont, par ordre décroissant, les acides gras, utilisés par 55% des souches, les acides aminés aliphatiques (51%), les acides aminés divers (44%), les hydroxyacides (43%), les acides dicarboxyliques (42%), les acides organiques divers (30%), les sucres (28%), les dérivés des sucres (27%), les alcools (21%) et les bases (19%).La plupart des souches étudiées utilisent un nombre élevé de substrats, mais aucun substrat n'apparaît comme universel.A partir de ces résultats et de ceux fournis par la littérature, les auteurs font remarquer que la proline, le glutamate, le pyruvate et le succinate sont les substrats les plus fréquemment utilisés, à la fois par les bactéries du plancton et par celles des sédiments côtiers et profonds. Ils en concluent que ces composés pourraient remplacer avantageusement le glucose lors des mesures du taux d'assimilation hétérotrophe des bactéries in situ.

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Aerobic heterotrophic bacteria isolated in front of the Rhône outlet. III. Organic substrates supporting growth.Two hundred strains of bacteria have been isolated from eutrophic surface waters; the substrates used as the sole source of carbon have been screened within 100 organic compounds belonging to different chemical groups.The fatty acids are the most frequently used substances, being attacked by 55% of the strains. The other compounds are ordered as follows: aliphatic amino-acids (51%), miscellaneous amino-acids (44%), hydroxyacids (43%), dicarboxylic acids (42%), miscellaneous organic acids (30%), carbohydrates (28%), carbohydrates derivatives (27%), alcohols (2i%) and organic bases (19%).Most of the strains attack numerous substrates, but none of these substrates is used by all the bacteria.From the data reported and from those in the literature, it can be stated that prolin, glutamate, pyruvate and succinate are attacked by most of the bacteria sampled both from surface waters and from neritic or deep sea sediments. It is pointed out that the measurements of bacterial heterotrophic assimilation rate should be run using these compounds instead of glucose.

     

Obtention de lignées permanentes d'hémocytes de blatte. Caractéristiques physiologiques et ultrastructurales

Two new cell lines were established from larval and adult cockroach haemolymph. The cells show typical characteristics of plasmatocytes, but under different conditions of cultivation, they modulate from small dividing cells (prohaemocytes) to large storing cells (granulocytes, adipohaemocytes etc.). Consequently, the very confusing haemocyte nomenclature must be reconsidered taking into account the cell physiology. Biochemical analysis of the metabolized culture medium established bacteriolytic activity and chitinase secretion (two enzymes). Moreover, in the same medium we found a macromolecular factor inducing spermatogenesis in cultured germinal cysts of the Cynthia silkworm. All these characteristics of in vitro haemocytes are discussed to explain the involvement of blood cells in insect physiology and especially in immunity, gametogenesis, and ecdysis.     

Ultrastructure des disques de patte de drosophile cultivésin vitro. Evagination,sécrétion de la cuticule nymphale et apolysis

Summary Ultrastructural observations were made on imaginal leg discs ofDrosophila cultured in vitro in Mandaron's medium M in the presence of - or -ecdysone.During evagination of discs in vitro the tight epidermal folds of the disc flatten out progressively and the cells change their shape.As the discs evaginate, the pupal cuticle is secreted at the apex of the cells: it comprises a three-layered cuticulin, an epicuticle and a thick endocuticle. Secretion of pupal cuticle always starts by the appearance of dense deposits at the apex of microvilli. Only the latter apparently participate in the construction of the three successive layers of the pupal cuticle.During disc development an abundant rough endoplasmic reticulum is formed. Nuclei and nucleoli become progressively enlarged. At the same time, the nucleus, initially located near the base of the cell, moves closer to the apical cell surface. Microtubules become fragmented as soon as evagination begins and are reorientated parallel to the cell surface (i.e. parallel to the new long axis of the cell) at the end of evagination.

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Ce travail a été réalisé avec l'aide du CNRS (Action thématique programmée) «Différenciation cellulaire», contrat n^o A 6554324.

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Ce mémoire représente une partie de la thèse qui sera soutenue par l'auteur devant l'Université Scientifique et Médicale de Grenoble.     

L’échec de fécondation en F.I.V.: intérêt d’un taux de récolte ovocytaire élevé et étude du taux de récidive

L’analyse de 1132 tentatives de FIV montre comment le taux de récolte détermine la fiabilité de l’estimation de l’échec de fécondation. L’étude de 64 couples ayant réalisé plusieurs tentatives dont une au moins s’est soldée par un échec de fécondation montre que 68,7% d’entre eux obtiennent des embryons lors d’une autre tentative. Les embryons replacés ont les mêmes aptitudes d’implantation et de développement que ceux obtenus par 130 couples ayant subi un premier échec d’implantation. Ces résultats sont mis en relation avec ceux obtenus par insémination subzonale après deux échecs de FIV.     

Régulation des excédents dans le développement du bourgeon de membre de l'embryon d'oiseau. Analyse expérimentale de combinaisons xénoplastiques caille/poulet

Summary In order to support the demonstration of the regulative capacity of the chick limb bud, already stressed by one of us (Kieny, 1964, 1967), heterospecific combinations were made between chick and quail tissues, the cells of the latter bearing a distinctive nuclear marker. A Japanese quail whole limb bud (stage-18 to 21 of H. H., wing or leg) was grafted distally onto the prospective zeugopod of a chick (stage-22) wing bud sectioned at the prospective wrist level. Thus, from a heterospecific surplus recombinant containing five prospective limb segments (stylopod and zeugopod from the chick host; stylopod, zeugopod and autopod from the quail graft), it was possible to obtain a normally shaped appendage that comprised either upper arm, lower arm and hand in the case of a wing bud graft, or heteromorphic upper arm, lower leg and foot in the case of a hind-limb bud graft. In these cases, regulation for excess appeared to take place mainly within the host tissues. The three proximal segments of the recombinant, namely the chick stylopod and zeugopod of the host's stump and the quail stylopod of the graft, became reorganized and gave rise to a single stylopodial segment, which usually contained a double stylopodial bone element, one of chick, the other of quail origin.The absence of development of the squeezed prospective zeugopod can be interpreted as follows: owing to an interaction with the stylopodial graft tissues, the zeugopodial cells of the juxtaposed stump boundary have shifted proximally their originally more distal positional values, so that they changed their prospective pattern of differentiation to that of stylopod. These reset zeugopodial cells combine with the stylopodial cells of host and graft and form a huge composite stylopod, in which, due to an asynchronous determination in the two species, chick and quail tissues do not cooperate fully for the development of a single bone.

Ce travail a été effectué avec l'aide de la D.G.R.S.T. (Action complémentaire coordonnée: Biologie de la reproduction et du développement, convention n^o 73-7-1661)     

Nouvelles espèces de dasycladales du crétacé inférieur de provence (S.E. France)

In the Lower Cretaceous of Provence Cylindroporella faronensis n. sp. and Cylindroporella massiliana n. sp. represent small size species with a limited number of branches. The former ranges from the Middle (or Lower p.p. ?) Berriasian to the Lower Valanginian, the latter is found in the Lower Hauterivian, but could appear earlier in other regions. Clypeina isabellae n. sp. is also a small size form with a fibrous, yellowish microstructure, close to Clypeina sulcata, it is restricted to the Middle (or Lower p.p. ?) and Upper Berriasian. Besides their biostratigraphic and palaeobiogeographic potential value this material from Provence is also interesting from an evolutionary point of view. At generic levels it shows distinctive patterns relatively to the “Cope law”.