Search

Space poses significant challenges for human intimacy and sexuality. Life in space habitats during long-term travel, exploration, or settlement may: detrimentally impact the sexual and reproductive functions of astronauts, restrict privacy and access to intimate partners, impose hygiene protocols and abstinence policies, and heighten risks of interpersonal conflicts and sexual violence. Together, this may jeopardize the health and well-being of space inhabitants, crew performance, and mission success. Yet, little attention has been given to the sexological issues of human life in space. This situation is untenable considering our upcoming space missions and expansion. It is time for space organizations to embrace a new discipline

Quality and timing of bone healing from orthopedic surgeries, especially lumbar spinal fusion procedures, is problematic for many patients. To address this issue, clinicians often use electrical stimulation to improve surgery success rates and decrease healing time in patients with increased risk of pseudarthrosis, including smokers and diabetics. Current invasive electrical stimulation devices require an implantable battery and a second surgery for removal. Piezoelectric composites within an interbody implant generate sufficient power under physiologic loads to deliver pulsed electrical stimulation without a battery and have demonstrated promising preclinical bone growth and fusion success. The objective of the current study was to assess the power generation and fatigue resistance of three commercially manufactured piezocomposite configurations in a modified implant design to demonstrate efficacy as a robust biomaterial within osteogenic implants. The three configurations were electromechanically assessed under physiological lumbar loading conditions, and all configurations produced sufficient power to promote bone healing. Additionally, electrical and mechanical fatigue performance was assessed under high load, low cycle conditions. All configurations demonstrated runout with no gross mechanical failure and two configurations demonstrated electrical fatigue resistance. Future piezoelectric implant design decisions should be based on power generation needs to stimulate bone growth, as mechanical fatigue efficacy was proven for all piezocomposite configurations tested.

SummaryLin28A and Lin28B selectively block the expression of let-7 microRNAs and function as oncogenes in a variety of human cancers. Lin28A recruits a TUTase (Zcchc11/TUT4) to let-7 precursors to block processing by Dicer in the cell cytoplasm. Here we find that unlike Lin28A, Lin28B represses let-7 processing through a Zcchc11-independent mechanism. Lin28B functions in the nucleus by sequestering primary let-7 transcripts and inhibiting their processing by the Microprocessor. The inhibitory effects of Zcchc11 depletion on the tumorigenic capacity and metastatic potential of human cancer cells and xenografts are restricted to Lin28A-expressing tumors. Furthermore, the majority of human colon and breast tumors analyzed exclusively express either Lin28A or Lin28B. Lin28A is expressed in HER2-overexpressing breast tumors, whereas Lin28B expression characterizes triple-negative breast tumors. Overall our results illuminate the distinct mechanisms by which Lin28A and Lin28B function and have implications for the development of new strategies for cancer therapy.

The Microprocessor, comprising the RNase III Drosha and the double-stranded RNA binding protein DGCR8, is essential for microRNA (miRNA) biogenesis. In the miRNA processing pathway certain hairpin structures within primary miRNA (pri-miRNA) transcripts are specifically cleaved by the Microprocessor to release ∼60–70-nucleotide precursor miRNA (pre-miRNA) intermediates. Although both Drosha and DGCR8 are required for Microprocessor activity, the mechanisms regulating the expression of these proteins are unknown. Here we report that the Microprocessor negatively regulates DGCR8 expression. Using in vitro reconstitution and in vivo studies, we demonstrate that a hairpin, localized in the 5′ untranslated region (5′UTR) of DGCR8 mRNA, is cleaved by the Microprocessor. Accordingly, knockdown of Drosha leads to an increase in DGCR8 mRNA and protein levels in cells. Furthermore, we found that the DGCR8 5′UTR confers Microprocessor-dependent repression of a luciferase reporter gene in vivo. Our results uncover a novel feedback loop that regulates DGCR8 levels.

The developmentally regulated RNA-binding protein Lin28 blocks processing of let-7 family microRNAs (miRNAs) in embryonic cells. The molecular basis for this selective miRNA processing block is unknown. Here we find that Lin28 selectively binds the terminal loop region of let-7 precursors in vitro and that the loop mediates miRNA processing inhibition in vivo. Additionally, we identify the domains of Lin28 required for this inhibition. These findings establish a regulatory role for the terminal loop of precursors in miRNA maturation and provide insight into the mechanism by which Lin28 negatively regulates let-7 processing.

A theoretical model has been developed which describes the growth of a photo-induced Bragg filter in a single-mode optical fiber. This model is derived from the coupled wave theory and takes into account Fresnel reflections at both ends of the fiber. The frequency response of the filter is the result of the combined effect of both the distributed and localized reflections. It has been calculated at various instants of the growth process and for various phase conditions at the Fabry-Perot fiber interferometer.

The visualization of traveling acoustic waves is achieved by means of acoustic stroboscopy. The limitations of the technique, interpretation of results, frequency range, and optical noise are reviewed. Two methods of noise reduction are studied: spatial filtering and holography. Optical holography of acoustic fields is also shown to offer the best advantages among the various methods of visualization outlined here.

A l’occasion d’une recherche de microfilaires Loa loa par hemolyse concentration sanguine chez un Camerounais presentant une hypereosinophilie, des œufs d’ascarides evoquant la morphologie de Toxocara canis ou T. cati sont decouverts et retrouves en nombre variable lors de six recherches successives dans les sept semaines suivantes. Ces œufs mesurant de 100 a 112 µ × 75 a 100 µ sont embryonnes a divers stades allant pour certains jusqu’a l’eclosion observee sous le microscope, liberant des larves de 437 a 504 µ . Ces phenomenes font supposer l’existence de vers adultes dans un biotope riche en oxygene du systeme circulatoire (ventricule gauche?). L’existence d’un incident pulmonaire (epauchement pleural) est difficile a mettre au compte certain de la parasitose (3 % de polynucleaires eosinophiles seulement dans le liquide de l’epanchement). Des traitements par thiabendazole (pour cure d’une anguillose associee) et diethylcarbamazine sont bien toleres, le premier s’averant limite voire nul sur « l’ascaridiose sanguine » alors que le second entraine la disparition definitive des œufs dans les prelevements de sang effectues a six reprises jusqu’au sixieme mois.

Evaluation of spinal implants is limited by difficulties in testing biological structures. Soft tissues primarily control spinal biomechanical responses. The objective of this study is to show controllability of the synthetic soft tissue properties of the mechanical analogue lumber spine. The development of an analogue spine would answer a multitude of clinical questions and improve implant design. Polyester fibers in a wave pattern were embedded in a shore-A F55 polyurethane matrix to mimic the nonlinear properties of human ligaments. Ligaments with four different volume fractions (Vf) of fibers were tested to failure in tension using specially designed jigs in a MTS MiniBionix. Polyester fibers oriented at +∕−30degrees were embedded in F55 polyurethane to simulate the annulus fibrosis (AF). Discs with three different Vf’s and F5 polyurethane for the nucleus pulposus were tested in compression to 1.25mm using a self-aligning jig. Displacement control was used for all specimens at a rate of 0.04230mm∕sec. For the ligaments, the initial stiffness and strain at toe was similar and the mean secondary stiffness in MPa was 187±5%, 307±5%, 422±2%, and 511±3% as the Vf increased. For the discs, the mean initial and (secondary) stiffness in N∕mm was 158±14%(658±6%), 150±5%(666±8%), and 74±3%(1230±2%) as the AF Vf increased. The results showed that synthetic soft tissue properties are controllable and properties measured fall within the range of human cadaveric literature values. A wide variety of analogue models can be developed utilizing the control of soft tissues.

An optical device has been developed to measure precisely and directly the real area of contact (RAC) between a glass prism and a machined polymeric surface. It is based on the perturbation of total internal reflection of a light beam in the region of contact between the two solid surfaces. The optical and electronic components of equipment intended for the measurement of the RAC, given in terms of percentage of the apparent surface of contact, were selected to provide improvements in the way of using this method and have permitted to reach a precision of about 1.5%, and a resolution of 0.05%, for finishes rougher than 1.0μm centre line average roughness value (CLA). These components also ensure measurements with a calibration factor independent of the material considered and its colouration. The design concepts are outlined, and typical experimental results for a thermoplastic material are presented, which show a good performance of repeatability. The variation of RAC with normal load was investigated with a large range of surface roughness of polymeric specimens. The results are included, and show that the real area of contact varies as 0.88 power of the normal load, with a proportionality constant dependent on the roughness of the contacting polymer surface.

Ascarids's eggs were found by blood concentration in a Cameroonese patient with hypereosinophilia. Eggs, similar to those of Toxocara canis or cati, were present in 6 blood concentrations carried out during 7 weeks. These eggs (70-75 x 100-112 microns) contained embryos and hatching of 437-504 microns long larvae was sometimes observed. The presence of adult worms in a well oxygenated localization (e.g.; the left ventricle) was supposed. A pleural effusion was also observed but the low number of eosinophils in the pleural fluid (3%) eliminated the responsibility of the parasite. The treatment by thiabendazole for an associated strongyloidosis was well tolerated but inefficient. On the contrary, the treatment by diethylcarbamazine, well tolerated, induced the disparition of the circulating eggs. This result was confirmed by 6 blood concentrations carried out during 6 months.

The authors compare the seropositivity against Toxoplasma gondii in 618 women from 13 to 55 years old coming from 6 different regions of Togo. The sera were examined for the presence of IgG by ELISA technic. The results show a significant difference with regions (extremes: 62 and 88% seropositive subjects) but religion, ethnic origin and diet do not seem to have any influence.

A discussion of the evolution of the HE12 (LP02) field, and thus the role of the core in HE11-H12 (LP01-LP02) local-mode coupling for a tapered ‘doubly-clad’ lightguide as may be formed by the combination finite-cladding fibre and external medium (i.e. outer cladding) is presented. Consideration of more than one interface injects interesting novel features into the local-normal-mode viewpoint: examination of the HE12 lobe maximum and field evolution leads to the discovery of a core/cladding bounce phenomenon (related to an HE12 leaky-mode property) as well as an intriguing coupling phase dependence.

We describe a method for the spectral analysis of Bragg filters in optical fibers based on the thermal expansion and index variation of the fiber. The method can only be equalled by the use of variable frequency lasers. A resolution of 30 MHz can easily be attained. The principle of the method is described together with the calibration procedure, and typical results are presented.

Resume A method is described which allows to visualize progressive surface waves without impairment dur to noise caused by imperfections and dirt particles on optical elements. An improvement of the signal to noise ratio by a factor of 160 is achieved.

Resume Les auteurs ont analyse 594 serums par les methodes ELISA (utilisant les differents coffrets proposes par les laboratoires bioMerieux, Biotrol et Flow) et les a 4 methodes classiques : immunofluorescence indirecte, agglutination directe et hemagglutination (reactifs bioMerieux et Fumouze). La difficulte de manipulation des methodes ELISA est compensee par l'objectivite de la lecture ; la reproductibilite nous a semble satisfaisante ; les resultats montrent une bonne correlation entre les 3 methodes ELISA et l'IFI en ce qui concerne les IgG ; quant aux IgM, la sensibilite de l'ELISA apparait superieure.

Brook trout, Salvelinus fontinalis , from hatching up to 31 weeks of age, were tested for susceptibility to IPNV at experimental temperatures of 5, 10 and 15°C. There were two different intervals of physiological age demonstrating specific characteristics of sensitivity to IPN viral infection in these fish. From 6 to 12 weeks of age, the peak mortality manifested itself around 21 days postinfection. In fish 15–21 weeks of age, mortality peaked as early as 10 days post-infection. Before or after these age intervals the fish did not appear to be sensitive to the virus. Moreover, the disease was produced at 10 and 15°C but fingerlings appeared resistant at 5°C.

Resume Les bilharzioses (Schistosomes), parasitoses tropicales d'importation, sont d'observation de plus en plus courante en France. L'analyse de 1159 cas observes porte sur un nombre sensiblement egal de bilharzioses urinaires africaines a S. haematobium et de bilharzioses intestinales a S. mansoni, provenant des Antilles et d'Afrique et sur quelques cas de bilharzioses rectales a S. intercalatum d'Afrique centrale. Moins d'un tiers des cas ont ete depistes lors de la premiere annee de transplantation, les autres beaucoup plus tardivement (bilharzioses chroniques bien tolerees cliniquement) et souvent decouvertes lors d'un bilan systematique. Les methodes directes de diagnostic donnent les pourcentages de succes suivant : analyse de selles 58%, analyse des urines 53%. La biopsie rectale, valable aussi bien dans la bilharziose urinaire qu'intestinale, est positive globalement dans 65% des cas. Le diagnostic direct n'a cependant ete possible que dans 61,5% des cas. Dans la bilharziose urinaire, l'examen cytoscopique peut aider le diagnostic par la decouverte d'aspects lesionnels caracteristiques. Il faut surtout insister sur l'interet de l'exploration radiographique qui, outre son eventuel apport au diagnostic permet d'apprecier l'importance des lesions de l'appareil urinaire souvent latentes. En raison de la faillibilite des methodes de diagnostic direct, les methodes sero-immunologiques revetent un tres grand interet dans le diagnostic des bilharzioses ainsi que dans la surveillance de l'efficacite du traitement, en particulier la technique de l'immunofluorescence indirecte a la fois particulierement sensible et specifique. La sensibilite est meilleure pour les bilharzioses intestinales a S. mansoni (91,3% et G.M.R.T. = 39,35) que pour les bilharzioses urinaires a S. haematobium. (83,5 % et G.M.R.T. = 20,07). Differentes explications peuvent etre apportees a ce phenomene. Le seuil de suspicion immunologique offrant toute garantie nous parait devoir etre fixe au taux de dilution du 1/40°. Les controles de l'efficacite therapeutique ont ete effectues un mois, 6 mois et un an apres traitement (et parfois au dela) et bases sur l'examen des selles ou des urines, le taux de l'eosinophilie et celui des anticorps fluorescents antibilharziens. La guerison n'est affirmee qu'au bout d'un an, avec la disparition des œufs, la normalisation du taux de l'eosinophilie et la disparition des anticorps (encore que dans certains cas cette negativation ne se produise que plus tardivement) ou leur forte regression par rapport au taux initial. Sur les 524 malades traites par le Niridazole (Ambilhar®), 137, soit 25% d'entre-eux ont pu etre controles selon les criteres precises ci-dessus avec l'obtention de 84,5% de guerison dans la bilharziose urinaire et 75% de guerison dans la forme intestinale. Ces chiffres qui confirment la meilleure efficacite du produit dans la bilharziose urinaire sont neanmoins inferieurs a ceux habituellement avances ; ils correspondent vraisemblablement a l'exigence de nos controles. Parmi les 126 malades soumis au traitement par l'Hycanthone (Etrenol®) 71 sujets, soit 56% de l'effectif traite ont ete surveilles regulierement, permettant de retenir 50 a 64,3% de guerison dans la bilharziose urinaire et 76,4% dans la bilharziose intestinale. Toutefois, de grâves accidents lies a l'hepatoxicite du produit se manifestant de maniere imprevisible incitent a l'utiliser avec la plus grande prudence. Le traitement de 30 malades par la 2-dehydroemetine® ne nous a pas permis, sur les 21 sujets qui ont pu etre suivis, d'obtenir les resultats satisfaisants signales par d'autres auteurs : 6 echecs sur 6 bilharzioses urinaires et 6 echecs sur 15 bilharzioses intestinales. Toutefois, l'apparente meilleure efficacite dans la bilharziose intestinale est utile a prendre en consideration lorsqu'il y a des contrindications a une cure par le Niridazole.

Resume Dans quatre cas d'anisakiase, des reactions serologiques positives ont ete obtenues en milieu gelifie avec un antigene Anisakis simplex. Les serums de ces malades peuvent egalement reagir avec les antigenes d'adultes d'Ascaris suum et Toxocara canis et de microfilaires Loa loa. Il n'a pas ete observe de fausses reactions avec les serums de 100 temoins normaux, et 150 affections diverses non parasitaires a l'exception d'un cas de sclerodermie. Dans les parasitoses des reactions croisees ont ete observees dans des distomatoses a Fasciola hepatica et surtout dans diverses nematodoses. Les reactions serologiques n'ont pas le temps de se positiver dans les anisakiases gastriques aigues. Elles sont tres utiles pour le diagnostic dans les formes subaigues ou chroniques ainsi que pour un diagnostic retrospectif car elles ne se negativent que dans un deali d'environ un an apres l'ablation endoscopique du ver.

Resume 368 cas de giardiase recueillis nous ont permis de preciser la frequence de cette affection selon le sexe et l'âge des malades, leur provenance geographique, de situer sa periodicite saisonniere et son association avec les autres parasitoses. Ces faits epidemiologiques, ainsi que les donnees cliniques et biologiques observees, sont examines et discutes par rapport aux travaux d'autres auteurs. Le diagnostic est biologique : l'examen corologique recherche les formes vegetatives du parasite ou ses kystes. Le traitement de choix actuel est le metronidazole. Son efficacite est nette ; toutefois des cures repetees sont souvent necessaires pour eradiquer cette parasitose trop souvent meconnue et negligee.

Intestinal infections are a major cause of mortality in domestic rabbits. Although a few pathogenic organisms have been associated with this type of infection, it is often impossible to demonstrate the presence of any etiologic agents.Recently viral particles were observed in the intestine of diseased rabbits submitted to our laboratory for diagnosis. A study was then initiated to evaluate the presence of viral agents in the intestine of rabbits showing clinical signs of enteritis. Viral particles with morphological characteristics of the Coronaviridae family were observed by electron microscopy in most specimens of fecal material obtained from sick rabbits. Such particles were not seen in the feces of healthy animals.These particles, which have a density of 1.07–1.18 g/cm3 on sucrose gradient, hemagglutinate rabbit red blood cells. Furthermore this virus has some antigenic relationship with the human coronavirus 229-E since immune serum to this virus blocks the hemagglutination of the rabbit erythrocytes.Antibody titers to this virus were detected in rabbit sera obtained from colonies with a high incidence of intestinal infections.When fecal material containing coronavirus particles were inoculated on various tissue culture systems, no cytopathic effects were observed.

Chez un Malien de 30 ans, en France depuis 2 ans les auteurs ont decouvert une triple infestation bilharzienne. Sur la biopsie rectale, a cote d’œufs typiques de S. mansoni et S. haematobium sont observes des œufs, que les caracteres morphologiques rapprochent de R. margrebowiei. Differentes hypotheses sont discutees. Toutefois le fait que cette espece n’ait jamais ete observee en Afrique occidentale ne permet pas de conclure formellement.

L’etude de l’evolution de T. cruzi (souche Tehuantepec) au niveau des differents segments du tube digestif de Triatoma megista permet de constater :1° La persistance au niveau de l’estomac et de l’intestin jusqu’au 24e jour de Trypanosomes degrades morphologiquement, mais ayant conserve leur pouvoir infectant.2° Au niveau de la phase rectale, l’apparition des Trypanosomes metacycliques a partir du 12e jour. Avant cette date, l’inoculation a la souris du contenu du rectum ne determine pas d’infection, ce qui confirme que les formes Crithidia ne sont pas infectantes.

The 21 nuclear hyperfine components of the P (33) line in the 6-3 band of the B ← X electronic band system of molecular iodine have been observed in the power spectrum of a Zeeman broadened He Ne laser operating at 6328 A with an iodine absorption cell within the cavity. The relative positions of the components have been measured with a precision of 0.36 MHz (0.000 012 cm −1 ), and their separations from the components of the R (127) line of the 11-5 band have been determined. A high resolution absorption spectrum of 127 I 2 over the 2.5 GHz tuning range of the laser has been obtained using an external multipass absorption cell. From the positions of the hyperfine components in the P (33) line it is possible to determine the difference in the nuclear electric quadrupole coupling constant eQq and in the spin-rotation constant C I for the two states, and the value of eQq″ . The results obtained are eQ q′ − eQ q″ = 1938.09 ± 0.34 MHz , C I′ − C I″ = 21.69 ± 0.96 kHz , and eQ q″ = −2980 ± 490 MHz , where the quoted uncertainties are one standard deviation. The rms deviation of the computed component positions is 0.35 MHz. The effects of second order (i.e., Δ J = ±2) interactions are shown to be significant. We have also recalculated the values of Δ eQq and Δ C I for the R (127) line.

The amplitude and phase distributions of a progressive acoustic wave are visualized simultaneously by means of acoustic stroboscopy. Two methods are described: (i) modulation of a laser beam by a progressive acoustic wave; (ii) modulation by a stationary wave. Spatial filtering of diffracted orders enables the progressive wavefronts to be seen as if they were stationary.

Apres un bref rappel de la morphologie de l’Entamoeba gingivalis et du Trichomonas tenax et des enquetes epidemiologiques anterieures sont exposes et interpretes les resultats d’un sondage portant du 1 250 sujets. Plus de 45 % des Francais hebergent des protozoaires buccauxEn conclusion sont discutees les causes favorisantes et determinantes de l’infestation par ces protozoaires.

Resume Une etude seroepidemiologique dans la population scolaire feminine de la ville de Sousse est entreprise afin d'evaluer le taux d'immunite a l'egard de la rubeole. 292 serums ont ete testes en utilisant la technique ELISA. Un serum est retenu positif et « protecteursi son titre est superieur ou egal a 20 UI/ml. Pour les tranches d'âges 8–11 ans et 16–20 ans, le taux de seropositivite est respectivement de 78,1 % et 88 % (P

The use of Méfloquine in the prophylactic treatment of malaria has, up to now, been hampered by the standpoint adopted by the WHO, the Conseil Supérieur d'Hygiène and some specialists, for whom Méfloquine should be administered only for short stays in areas of strong chloroquine-resistance. This policy, which prevents many travellers and overseas residents from benefitting from one of the most effective prophylactic treatments on the market today, thereby indirectly causing a number of pernicious cases of malaria, is based on the unfounded, unproved premise that wide use of this drug would foster the development of méfloquine-resistance or on side-effects, which are in fact rarely of any consequence and always curable. The efficacity of this drug should ensure that it is used for the basic prophylactic treatment of malaria in chloroquine-resistant areas, whatever the degree of this resistance and the length of stay involved, on condition that care is taken as to the tolerance of this drug in the early stages of treatment.

Retrospective study has been conducted in the parasitic and tropical diseases department of the hospital Cochin, based on observations made between 1966 and 1985 on antibody rates in sera of 709 bilharziasis patients (S. mansoni). This study shows a great difference of immunologic reaction between the group of patients from French West Indies (458 patients) and the one of the group of patients from Africa South of Sahara (189 patients). Such an observation leads the authors to suppose a difference between strains of schistosomes from Black Africa and French West Indies.

The study of anti Schistosoma mansoni and anti Schistosoma haematobium sera by homologous and heterologous antigen shows that Schistosoma haematobium has an immunogenic strength as good as that of Schistosoma mansoni. The joint use of the two antigens can be useful in epidemiologic investigations in Africa so as to track down seats of Schistosoma mansoni and Schistosoma haematobium and the prevalence of the infection.

The risk of acquired toxoplasmosis during pregnancy (1.2% of susceptible women) and of transmission of Toxoplasma gondii to the fetus (1% of neonates) was estimated from results of serial serological tests done in 15 132 pregnant women from 1977 to 1982. Congenital toxoplasmosis was studied in the product of 47 induced abortions and in 34 neonates. In aborted fetuses, congenital toxoplasmosis was established by serological tests in 3 cases and based on histological findings in 4. Among the neonates, 11 cases are reported; the 5 severe cases are due to early contamination.

Fluorescent antischistosomiasis antibodies appear earlier in mice infected by 150/200 cercariae than in those who only received 20. The use of a homologous antigen in mice infected by S. mansoni or S. haematobium allows earlier and more important responses. The infections by S. haematobium seem to determinate in mice a more important immune responsiveness. Is it a specific parasitic manifestation (S. mansoni being better adapted to rodents?).