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861.
Nottola SA Heyn R Camboni A Correr S Macchiarelli G 《Microscopy research and technique》2006,69(6):508-516
The use of somatic cells for cocultures during in vitro fertilization (IVF) is currently finalized to obtain a higher number of healthy and viable embryos with a high potential of implantation. Among the different cell lines that can be used as feeder cells for cocultures, granulosa cells (GCs) are autologous cells, safe and easy to recover. The aim of the present study was to analyze the fine structure of human GCs used in a coculture system to evaluate, from a morphodynamic point of view, their role in supporting embryo development. GCs were collected during oocyte pick-up, 36 h after human chorionic gonadotropin administration, from patients undergoing IVF procedures, who had given their informed consent to be included in this protocol. After coculture, GCs were fixed and processed for light microscopy (LM) and transmission electron microscopy (TEM). By LM, GCs appeared as clusters of loosely packed cells, irregularly rounded or polyhedral in shape, varying in diameter from 18 to 25 microm. Mitotic cells, as well as regressing elements (with pyknotic nuclei or dense cytoplasm) and cell fragments were occasionally observed. By TEM, the plasma membrane was irregular due to the presence of cytoplasmic evaginations. Linear and annular gap junctions between neighboring GCs were found. GC nuclei, rounded and eccentrically located, contained finely dispersed chromatin, one (often two) prominent nucleoli and, infrequently, peripheral patches of heterochromatin. Numerous organelles populated the GC cytoplasm, among them, mitochondria were rod-shaped or elongated, usually provided with tubular-vesicular cristae but occasionally showing atypical, longitudinally oriented cristae. Membranes of smooth endoplasmic reticulum, Golgi stacks and vesicles, secretory-like granules, cisternae of rough endoplasmic reticulum (RER), free ribosomes and polysomes, lysosomal-like bodies, microfilaments, and lipid droplets were also seen in the GC cytoplasm. In most cells, RER was scarcely represented and numerous lipid droplets filled the perinuclear space. On the contrary, some GCs contained an abundant RER and rare lipid droplets scattered in the cytoplasm. In conclusion, our data demonstrated the presence, in a coculture system, of GCs provided with ultrastructural characteristics typical of healthy, metabolically active, mostly steroidogenic cells. Protein-synthetic cells have also been detected. These data, evaluated at the light of biochemical and clinical studies, sustain the capability of human GCs cocultures to positively affect early embryo development in vitro by the secretion of steroids and proteins, putative "embryotrophic" factors. 相似文献
862.
Dharod JM Pérez-Escamilla R Paciello S Bermúdez-Millán A Venkitanarayanan K Damio G 《Journal of food protection》2007,70(8):1927-1932
The study was conducted to compare and identify the magnitude of differences between self-reported and observed food safety behaviors among women preparing a chicken and salad dish at home. The observed food safety practices also were compared according to sociodemographic variables and prior food safety education. Sixty Puerto Rican women who were the main meal preparers for their households were recruited in Hartford, Conn. Three household visits were made to (i) deliver food ingredients to prepare the chicken and salad meal, (ii) conduct household observation, and (iii) conduct a self-reported survey. The difference between self-reported and observed behaviors varied across food handling and sanitation behaviors. There was a high level of inaccuracy for socially desirable behaviors such as hand washing; the vast majority of participants reported practicing these behaviors but they were not observed doing so. Cutting board washing also was considerably overreported, questioning the validity of these self-reported data for regression analyses. There was a significant association (P < 0.05) between proper thawing method and prior food safety education, use of cutting board and higher income, and washing tomatoes and having a positive attitude towards food safety. Results revealed that overreporting errors must be considered when analyzing and/or interpreting data derived from self-reported food safety consumer surveys and that food safety education and positive food safety attitudes are associated with recommended food safety behaviors. 相似文献
863.
Lazzeri L Cascone MG Danti S Serino LP Moscato S Bernardini N 《Journal of materials science. Materials in medicine》2007,18(7):1399-1405
Biodegradable synthetic polymers such as poly(lactic acid) (PLA) are widely used to prepare scaffolds for cell transplantation
and tissue growth, using different techniques set up for the purpose. However the poor hydrophilicity of these polymers represents
the main limitation to their use as scaffolds because it causes a low affinity for the cells. An effective way to solve this
problem could be represented by the addition of biopolymers that are in general highly hydrophilic. The present work concerns
porous biodegradable sponge-like systems based on poly(l-lactic acid) (PLLA) and gelatine. Morphology and porosity characteristics of the sponges were studied by scanning electron
microscopy and mercury intrusion porosimetry respectively. Blood compatibility was investigated by bovine plasma fibrinogen
(BPF) adsorption test and platelet adhesion test (PAT). The cell culture method was used in order to evaluate the ability
of the matrices to work as scaffolds for tissue regeneration. The obtained results indicate that the sponges have interesting
porous characteristics, good blood compatibility and above all good ability to support cell adhesion and growth. In fact viable
and metabolically active animal cells were found inside the sponges after 8 weeks in culture. On this basis the systems produced
seem to be good candidates as scaffolds for tissue regeneration. 相似文献
864.
Sergio?GalvagnoEmail author Sabrina?Portofino Giovanni?Casciaro Stefania?Casu Luigi?d’Aquino Maria?Martino Antonio?Russo Giovanni?Bezzi 《Journal of Materials Science》2007,42(16):6878-6886
The synthesis of beta silicon carbide (β-SiC) powders by carbothermal reduction of silica with carbon in a high temperature
tube furnace was investigated. As carbon source, fine carbon-containing char from biomass gasification was used, in order
to verify the feasibility of producing a high added value material starting from waste residue, and to promote the gasification
processes as alternative route of energy production by the proper by-products exploitation. Starting mixture was prepared
by mechanically mixing silica and char in the weight ratio of SiO2:C of 1.514; the mixture then reacted in a tube furnace at temperature of 1,550 °C at different residence times (1, 1.5, 2
and 2.5 h), at a constant flow rate of 0.8 dm3 min−1 of argon. The reaction products were characterised with XRD, FTIR spectroscopy and transmission electron microscopy (TEM).
The process turned out to be capable of producing high quality SiC powders, suitable for making ceramic materials and composites;
the product shows an uniform spherical shape, a very fine particle size (within the range of 30–100 nm) and a purity degree
varying from 70% to 95%, depending on the residence time. 相似文献
865.
Galdiero S Falanga A Vitiello M D'Isanto M Collins C Orrei V Browne H Pedone C Galdiero M 《Chembiochem : a European journal of chemical biology》2007,8(8):885-895
We have identified a putative membrane-interacting domain preceding the transmembrane domain of the Herpes simplex virus type 1 (HSV-1) glycoprotein H (gH). Peptides derived from this region interact strongly with membranes and show a high tendency to partition at the interface. This region is predicted to bind at the membrane interface by adopting an alpha helical structure. Peptides representing either the HSV-1 gH pretransmembrane region or a scrambled control with a different hydrophobic profile at the point of interface have been studied. The peptides derived from this domain of gH induce the fusion of liposomal membranes, adopt helical conformations in membrane mimetic environments and are able to inhibit HSV-1 infectivity. The pretransmembrane region appears to be a common feature in viral fusion proteins of several virus families, and such a feature might be related to their fusogenic function. The identification of membrane-interacting regions capable of modifying the biophysical properties of phospholipid membranes lends weight to the view that such domains might function directly in the fusion process and could facilitate the future development of HSV-1 entry inhibitors. 相似文献
866.
Aulenta F Catervi A Majone M Panero S Reale P Rossetti S 《Environmental science & technology》2007,41(7):2554-2559
The ability to transfer electrons, via an extracellular path, to solid surfaces is typically exploited by microorganisms which use insoluble electron acceptors, such as iron-or manganese-oxides or inert electrodes in microbial fuel cells. The reverse process, i.e., the use of solid surfaces or electrodes as electron donors in microbial respirations, although largely unexplored, could potentially have important environmental applications, particularly for the removal of oxidized pollutants from contaminated groundwater or waste streams. Here we show, for the first time, that an electrochemical cell with a solid-state electrode polarized at -500 mV (vs standard hydrogen electrode), in combination with a low-potential redox mediator (methyl viologen), can efficiently transfer electrochemical reducing equivalents to microorganisms which respire using chlorinated solvents. By this approach, the reductive transformation of trichloroethene, a toxic yet common groundwater contaminant, to harmless end-products such as ethene and ethane could be performed. Furthermore, using a methyl-viologen-modified electrode we could even demonstrate that dechlorinating bacteria were able to accept reducing equivalents directly from the modified electrode surface. The innovative concept, based on the stimulation of dechlorination reactions through the use of solid-state electrodes (we propose for this process the acronym BEARD: Bio-Electrochemically Assisted Reductive Dechlorination), holds promise for in situ bioremediation of chlorinated-solvent-contaminated groundwater, and has several potential advantages over traditional approaches based on the subsurface injection of organic compounds. The results of this study raise the possibility that immobilization of selected redox mediators may be a general strategy for stimulating and controlling a range of microbial reactions using insoluble electrodes as electron donors. 相似文献
867.
Fonda Umani S Milani L Borme D de Olazabal A Parlato S Precali R Kraus R Lucić D Njire J Totti C Romagnoli T Pompei M Cangini M 《The Science of the total environment》2005,353(1-3):218-231
The temporal dynamics of microphytoplankton, microzooplankton and mesozooplankton were monitored over 37 months in the Adriatic Sea in order to identify alterations in the plankton structures, which can lead to, or enhance the production of macro-aggregates, that affected the entire northern basin in summers 2000 and 2002, and to assess any negative effects of mucilage on plankton temporal patterns. Samples were collected monthly, from June 1999 to July 2002, on three transects at 9 stations across the northern and central Adriatic Sea. Besides the high year-to-year variations in abundances and taxonomical composition, plankton communities only showed a clear seasonal succession during 2001, when since April a grazing food web developed and was able to control large sized phytoplankton increase. In spring-summer 2000 and 2002 consumer abundances remained quite low and the dominant mesozooplankton summer species (Penilia avirostris) did not reach its usual summer maximum. The lack of an efficient top control was more evident on the northernmost transect, where generally grazing food web prevails over the microbial one. A large part of the microphytoplankton blooms, although not particularly intense, was exported to the bottom in the particulate phase, where it was processed by bacteria, enhancing the production of refractory dissolved material. 相似文献
868.
Fontanesi L Beretti F Dall'Olio S Portolano B Matassino D Russo V 《The Journal of dairy research》2011,78(1):122-128
Massese is an Italian sheep breed, with black or grey coat colour, mainly reared in the Tuscany and Emilia Romagna regions. Recently, the emerging interests in this breed have resulted in the production of Pecorino cheese obtained with only Massese milk. In order to be profitable, this marketing link between Massese breed and its products should be defended against fraudsters who could include milk of other sheep breeds or cow milk in Massese labelled productions. To identify the genetic factors affecting coat colour in sheep, we have recently analysed the melanocortin 1 receptor (MC1R) gene and identified several single nucleotide polymorphisms (SNPs). In this work, as a first step to set up a DNA based protocol for authentication of Massese dairy products, we further investigated the presence and distribution of one of these SNPs (c.-31G>A) in 143 Massese sheep and in another 13 sheep breeds (for a total of 351 animals). The Massese breed was fixed for allele c.-31A, whereas in all other breeds allele c.-31 G was the most frequent or with frequency of 0?·50. At the same nucleotide position the cattle MC1R gene carries the G nucleotide. Using these data we developed a method to detect adulterating milk (from other sheep breeds or from cow) in Massese dairy products based on the analysis of the c.-31G>A SNP. We first tested the sensitivity of the protocol and then applied it to analyse DNA extracted from ricotta and Pecorino cheese obtained with only Massese milk or obtained with unrestricted sheep and cattle milk. To our knowledge, this system represents the first one that can be used for breed authentication of a sheep production and that, at the same time, can reveal frauds derived from the admixture of milk of an unreported species. 相似文献
869.
Piccione G Messina V Schembari A Casella S Giannetto C Alberghina D 《The Journal of dairy research》2011,78(4):421-425
In dairy cows the period of transition from late gestation to early lactation is recognized as inducing considerable metabolic adaptation. The aim of this study was to analyse modifications in serum protein values occurring during the dry and the transition period and during lactation in a group of five Holstein cows of high average milk production. For all subjects, selected on the basis of their pregnancy status, blood samples were collected at different physiological phases: dry period (-60, -30 d to calving), transition period (almost 7 d to calving, 7 d after calving), and lactation (weeks 2, 5 and 15 after calving), for a total of eight blood samples for each cow. On each blood sample total proteins and electrophoresis analysis were performed. On the data obtained, normally distributed (P<0·05, Kolmogorov-Smirnov's test), one-way Repeated Measure Analysis of Variance (ANOVA), was applied to evaluate the influence of different stages of gestation and lactation on the considered parameters. Results showed a significant effect on total proteins, α1-globulins, β-globulins, γ-globulins and albumin/globulin ratio. Most of the detected modifications were related to the transition from gestation to lactation, indicating that it is a period of great metabolic stress for cows. On the basis of the obtained results we can affirm that the pattern of serum protein fraction rn could give information about dehydration, plasma volume expansion and hepatic function occurring during the peripartum period in dairy cows. 相似文献
870.
Pier Paolo Pompa Giuseppe Vecchio Antonio Galeone Virgilio Brunetti Stefania Sabella Gabriele Maiorano Andrea Falqui Giovanni Bertoni Roberto Cingolani 《Nano Research》2011,4(4):405-413
The growing use of nanomaterials in commercial goods and novel technologies is generating increasing questions about possible
risks for human health and environment, due to the lack of an in-depth assessment of their potential toxicity. In this context,
we investigated the effects of citrate-capped gold nanoparticles (AuNPs) on the model system Drosophila melanogaster upon ingestion. We observed a significant in vivo toxicity of AuNPs, which elicited clear adverse effects in treated organisms, such as a strong reduction of their life span
and fertility, presence of DNA fragmentation, as well as a significant overexpression of the stress proteins. Transmission
electron microscopy demonstrated the localization of the nanoparticles in tissues of Drosophila. The experimental evidence of high in vivo toxicity of a nanoscale material, which is widely considered to be safe and biocompatible in its bulk form, opens up important
questions in many fields, including nanomedicine, material science, health, drug delivery and risk assessment.
相似文献